Britain's Most Fragile Treasure

For six centuries, before the advent of oil painting,

medieval artists used light

to describe the wonders of the Christian faith.

The medium was glass...

..painted and cut into forms to create images.

The stained glass in the great churches of medieval Britain

could communicate stories to a population that was largely illiterate.

The light pouring through the windows is the light of the Lord,

the light of Heaven.

And so the medium and the images convey the same message -

this is the Truth.

God, the Father, sits at the highest point of the East Window

in York Minster.

At 78 feet in height,

it's the single largest medieval stained-glass window in the country.

I look on this as England's Sistine Chapel,

made 100 years before Michelangelo's masterpiece.

And it's just as ambitious in its scope.

What these 311 stained-glass panels represent, in fact,

is the entire history of the world,

from the first day...

..to the Last Judgment.

I want to unlock the secrets of these extraordinary images

by looking inside them, to uncover how they were made

and what they mean.

And that's possible now because the panels are being cleaned and restored

as part of a huge conservation project.

I'm going to use these panels to travel back in time

through the 600 years of history

that are preserved within the individual pieces of glass,

to discover details that would normally be impossible to see...

"Henry Bewlay new leaded this light

"July 17th, 1825".

Fantastic!

..and to reveal exactly how medieval artists made images

of such delicacy and complexity using the simplest of tools.

Because it's through this process of restoration

that we can begin to understand how these panels were made,

who made them,

and how they must have appeared to the people who first saw them.

The East Window of York Minster

is far more than a work of artistic genius.

It's a window onto the medieval world

and the medieval mind,

telling us about who we once were, and who we still are,

preserved in the most fragile medium of all -

..glass.

The City of York is dominated by the presence of the Minster.

It's the largest medieval Gothic cathedral in northern Europe.

And the fact that it was built here is a clue

as to just how significant this most historic of cities has been

in British history.

And in my work as a medieval art historian,

it's somewhere I've become very attached to as well.

York is a hugely important place for me.

The medieval past oozes out of the cobbled streets

and the quirky buildings.

I was so seduced by the city that I ended up studying,

living and teaching here for many years.

But York's always been an important place. Under the Romans,

it was the major town of the north, known as Eboracum,

and the Vikings founded their flourishing trading town of Jorvik

on the banks of the River Ouse.

Into the medieval period, it was the second city of England,

a commercial hub, and for a time,

the administrative capital of the country.

And the building that was at the heart of this medieval power base

is also, I think, one of our greatest art treasures.

York has had its own archbishop since the eighth century,

with authority over the whole of the North of England

up to the Scottish border.

And that authority was reflected in the city's cathedral,

which was repeatedly rebuilt and expanded

over a period of more than 700 years.

Until the Gothic marvel we see today was finally completed in the 1470s.

To enter a cathedral in medieval times

must have been an overwhelming experience.

The soaring architecture, the effect of light and space,

combined with the smell of incense and the sound of singing

must've made for an intoxicating, almost transcendental experience.

The medieval architecture in these spaces

was designed to make the individual feel small

and awe-inspired by the wonder of God's creation.

But if it's the stonework that gives this building its grandeur,

it's the stained glass, I think, that makes it beautiful.

York Minster has the largest collection of medieval glass in the country

and the crowning glory is the spectacular East Window.

Built in just three years, between 1405 and 1408,

it's a towering tribute to the creative heights

that stained glass can soar to.

And it's one of my favourite historic works of art.

But when you come to the east end of York Minster today,

the first thing you notice

is that this magnificent work of medieval art isn't here.

This enormous screen, which is a full-size photographic reproduction,

gives you a very powerful sense of the scale of the window.

But the glass itself has been removed.

The window is being conserved by a team at York Glaziers Trust.

Conservators are cleaning and restoring...

..and re-leading the glass panels just as diligently and methodically

as the medieval craftsmen who first worked on them.

And it's providing a unique insight

into how the window was actually made.

'Sarah Brown is the director of the programme.'

Sarah, it's wonderful to be in presence of these stained-glass windows.

In terms of approaching the panels as a conservator...

-Yes.

-..they're out of the tracery now.

-Yes.

-What do you do then?

-The very first thing we do

is make a one-to-one rubbing of every single panel,

so that we have a very detailed chart

of where each individual piece of glass sits within the panel

and we know exactly where the lead lines are positioned.

And all the panels are photographed as they come into the workshop.

We note if there are any areas of particular fragility.

Only then do we begin the process of dismantling very carefully.

-Because these are paintings, aren't they?

-They are paintings, indeed.

If we look at how paint is applied, what can you tell us about that?

Well, first of all, extraordinarily expert

-in the quality of the painting.

-Hmm.

-Layers of wash used

to model the figures, paint, of course, applied

not just to one surface, but to both surfaces,

so the treatment of the horse here,

we've got a lot of painting on the inside surface of the glass,

but also, to create this dappled effect,

which now has also been slightly corroded,

this dark horse decorated with the external application of glass paint.

-Very, very complex layered effects of glass painting.

-Absolutely.

The East Window was created

during a golden age for stained glass in this country,

around the beginning of the 15th century.

But the tradition had been evolving over many hundreds of years

to get to this point.

'This is the Victoria and Albert Museum in London

'and I've come to meet Professor Richard Marks,

'who's an authority on the history of stained glass.'

These are two panels done in the 1240s

for one of the most important Gothic buildings of the time -

the Sainte Chapelle in Paris. You see the predominant colours

-are red and blue here...

-Yes.

..and the tonality is dense.

It's not about light so much.

Think of a wall with glass, a wall made of glass,

and one which you can make perhaps more interesting than a wall.

You can do things with it and colour in terms of design, which is what you've got here.

And you can tell stories through it.

-So, we're looking at something quite sophisticated.

-Yes.

-But how did we get to this point?

-There's a good question.

-The trouble is, we've got enormous gaps...

-Mm.

Most of the glass we know, we know from about 1140 onwards.

What happens before then? Well, the fragments that have been found at Jarrow and Monkwearmouth

and other Saxon sites don't have any painting on them at all.

They're just bits of coloured glass.

And I think what we have to think about there

is imagine mosaic windows. A kind of kaleidoscope of different colours,

different shapes leaded together in the window.

But I don't think there's any evidence of figurative work

before the 9th century in Europe.

What's striking about the earliest painted windows we have

is that they still resemble a mosaic of bold colours

separated by dark bands of lead.

But then, in the 14th century, there's a dramatic change.

So, Richard, what's the significance of this panel, then?

It's a technical significance,

which is a very fine example here of a technique

which was of fundamental importance in glass painting

in the 14th century.

It's the application of silver stain,

which was used as a solution applied to this glass.

Now, what this enabled glass painters to do

is to paint two colours, if you like, white and yellow,

without the use of leading.

-You can see that round the head of the angel down here.

-Wow.

There's no lead at all.

Now, of course, that had an enormous impact on translucency of glass.

And this does enable this kind of much more use of white glass

and painted white glass in the late 14th and early 15th centuries.

So, we've seen this progression, then, in stained glass,

from these quite bejewelled

-blue and red and vibrant colours...

-Yes.

-..of the 12th and 13th century

through this technological development of the staining...

-Yes.

-..the use of yellow stain, and then, we reach panels like this.

What you're looking at here

is not just a masterpiece of glass painting,

but a masterpiece of painting on glass of the late 14th century.

What you have here,

they're not just flat figures,

but the faces are animated by very detailed shading.

But look at the way the shading

brings out of the depth, the three-dimensional nature,

these figures project out of their niches,

-they're coming towards you...

-Yes.

-..and this is something where,

-really, these feel like sculpture, don't they, in paint?

-Mm.

-So, the great East Window at York...

-Yes.

..is it following on this tradition?

-I think it's another way of looking at it.

-Right.

Of course, in the East Window, each panel tells a story.

But what makes that window so incredibly impressive

is it's the east wall, which is not masonry at the Minster,

it's all glass.

It's a punctuation at the end.

And it's not one done with stonework,

it's done with colour and vibrancy and translucency.

And that comes out of a tradition which is peculiar to England,

of cliff-like east ends in English Gothic cathedrals.

And it is monumental.

Conserving the East Window will be an equally monumental task.

It's expected to take eight years to complete.

And this isn't the first time the window has been dismantled.

All the glass in the Minster was taken down

just before the outbreak of the Second World War

as a precaution, before being restored

and re-installed during the 1940s and '50s.

But even that was only one of many conservation projects

that have taken place over the centuries.

And they've each left their mark in the most unexpected way.

We know of three, possibly four interventions.

Two of them are documented with some degree of certainty.

The 1824 to '27 re-leading of the window,

and then, of course, the post-Second World War work.

And the window has evidence of all of those different phases of repair.

So, in this panel, which is the famous image of God the Father,

from the very apex of the window, this very bright-greeny glass,

is not medieval glass.

We know that it dates from the 1820s.

And in part, that's because it has a lot of graffiti,

listing the names of the people who were involved in the repair process.

-Gosh.

-So "Henry Bewlay new leaded this light, July 17th, 1825".

-Fantastic! So, it's a document of that process.

-A document...

-There's other dates.

-Exactly. We have here

-some names scratched in 1946.

-Yeah.

Which was after the repair of this part of the window,

following the Second World War. And some of them, of course,

-rather more visible than we would like them to be.

-Mmm.

So, somebody, unfortunately, has scratched "top"

-right across God's forehead.

-Oh, dear!

And, as is now becoming clear, the work of previous restorers

has not always matched the skill of the original, medieval craftsmen.

The first thing we'll do is take a good look at the panel

before any of the work is done, and just see the history

that this panel has been through.

I think, in actual fact, this particular panel is a good survivor,

it does have a large quantity of its original glass within it.

More so than many. But it's covered in this very, very dense leading.

You can see it's actually layered up, just this dense block of lead, blocking all that light.

That's right, and we know as part of the previous restoration campaign in the 1940s and '50s

that they were re-leading all the panels

and they were using this very heavy gauge of lead.

So, this lead is not particularly of a great age,

but we feel it's so disfiguring in its gauge,

in its strength and its weight

that so much is hidden beneath that lead.

Not only had the images been obscured in this way,

but broken pieces within the panels have been repaired with even more lead.

-Which bits are additional repairs?

-Well, if we take the angel's wing,

-clearly there's impact damage.

-In the centre, yeah.

And the extra lead radiating from that impact damage

have been added in, obscuring much of the detail to the wing.

The painted parts of the glass have been badly affected in other ways.

In this particular panel, we have quite a bit of paint loss.

-Yeah, I see.

-Some of the facial features are very much disappearing.

In part, this is due to corrosion of the surface of the glass,

it could also be, in part, due to over-zealous cleaning in the past.

Right, so actually scrubbing the surface?

-Probably scrubbing a bit too hard.

-Wow.

But once all that heavy 1940s lead has been removed,

you can begin to see beyond the history of past damage,

and really appreciate how beautifully the window was made.

So, I can see two panels down here. This really illustrates it...

-It does.

-..the difference between having the leads in situ and then revealed.

-Exactly.

Exactly.

It's so exciting to see some of the lost detail coming to light.

-Exactly. It is one of the great masterpieces of the Middle Ages.

-Mm.

The quality of the painting, I mean, the lively characterisation

of the faces, for example, the way in which paint is rubbed out gently

to give highlights across the top of the nose.

The treatment of the hair and beard -

the hair picked out with yellow stain,

the beard left without.

It's an astonishing piece of glass painting virtuosity, really.

It really does to come to life here.

When you look at a panel like this, you can see just how tightly fitting,

how intricately cut the glass is, how these pieces were designed

to be sitting very closely together, almost like a very elaborate

-and extremely skilfully cut jigsaw.

-Mmm.

And the complexity of the shapes cut is all the more remarkable

because we know that the kind of tools being used, to the modern eye,

look rather cumbersome. For example, the grozing iron, this notched tool,

which sits over the edge of the glass and nibbles away at the edge

and leaves a very, very distinctive telltale cut edge to the pieces,

which we can see very clearly in a number of the pieces of glass.

-Can you show me that? Yeah.

-It creates a very typical nibbled edge.

-Yes.

-Which is chamfered inwards. That's from the movement of the grozing iron.

-Absolutely.

-Wow.

Most medieval stained glass was made by artists and craftsmen whose names are lost to history.

But of all the remarkable things about the East Window,

perhaps the most surprising is that we actually know who made it.

His name was John Thornton, and from the evidence that survives,

we can piece together some of the story of his life and career,

and, in particular, his work on the East Window.

We know he came from Coventry and he was invited to come here

either by Archbishop Scroope, or perhaps by Walter Skirlaw,

the bishop of Durham, who gave the window.

Both of those bishops had, for a time, lived and worked in Lichfield

and Coventry diocese, so they might well have known him there.

He was painting in a style which would have been recognised

by the great masters throughout early 15th-century Europe.

He was painting in this wonderfully painterly, soft style,

that we tend to call the International Gothic.

It's a style which has comparators all over northwest Europe

and it's a style which is associated with the highest quality

and most prestigious projects throughout Europe.

So, he was really brought in as a kind of an exceptional figure,

a sort of superstar artist, to be entrusted with this great window,

the biggest window in the Minster.

And there is this mysterious panel from the top of the window,

-which is believed to be a monogram.

-Mm.

We have the letters "I", which in the Middle Ages would stand in for "J",

so John, Johannes, and "M", which could be for Master, Magistere,

and a "T" at the bottom, so this might be a monogram representing John Thornton.

The conclusive evidence that this is the work of John Thornton

is not to be found in the window itself, but in the contract for the making of it,

which was drawn up by the Dean of York and the Chapter - the clerics who advised him.

The Dean and Chapter have unwittingly left us a fascinating insight

into how a medieval star artist was expected to go about producing a landmark work of art.

Historian Tim Ayers has studied the contract for the East Window in detail.

We've got these documents here. What do they tell us about John Thornton?

Well, this is a 17th-century transcript of the Latin contract

for the glazing of the Great East Window.

There is also a shorter translation.

In terms of Thornton's own work, it makes...

a highly interesting distinction.

"It obliges himself, with his own hands, to portraiture the said window

"with historical images and other painted work,

"in the best manner and form that he possibly could.

"And likewise, to paint the same,

"where need required,

"according to the ordination of the Dean and Chapter."

There seems to be a distinction

between the portraiture and the painting,

that the design would, in the first instance, have been drawn up,

probably on a small scale, by the glazier, and it seems likely that

the portraiture described here is this initial design phase.

The painting, he apparently is only required to do so much

as the Dean and Chapter should require him.

This fits in well with what we know about the collaborative nature

-of the medieval glaziers' workshop.

-Mmm.

Many people would be involved in cutting the glass,

laying it on the table, painting it, firing it, leading it up and so on.

What we have here is an insight into what the man responsible

for the glazing workshop was expected to do himself.

The contract seems to suggest, then, that he's both a painter

and a manager of quite high standing.

And that is reflected in the pay. He's paid a lot for this work.

-The contract is very specific about what he would be paid.

-Mm.

And it reveals that there are a series of staged payments,

which clearly provide him with incentives.

He should be paid four shillings sterling a week.

He will also be paid a hundred shillings every year,

and at the end of the contract,

the Dean and Chapter reserve the right to pay him a bonus of ten pounds in silver.

-Wow. And that's a lot, isn't it?

-This is a great deal of money.

-The king's glazier, at this period, was paid one shilling a day.

-Mm.

Here, John Thornton is being paid four shillings a week,

but with these extra payments and with a commitment for work

over a period of three years.

What else do we know about him? Is there any other evidence for him?

There is evidence for him in the Freeman's register of York.

-Ah!

-This was a privilege that would have allowed John Thornton,

as a Freeman, to operate within the city.

But that's not all.

In 1411, just a year after registering in York,

Thornton is back in Coventry, where he takes out a 60-year lease

on a house, only to reappear again in York some years later.

So, although no other contracts survive for Thornton

besides the East Window, it seems he was dividing his time

between two cities, more than 100 miles apart.

And that offers a tantalising possibility - that many more windows

could be attributed to this seemingly very successful artist.

Is there historical evidence, then, for him being in both these cities?

Well, those who have been fascinated by the contract

and intrigued by the artistic personality of John Thornton

have tried to identify an oeuvre for him, if you like,

a body of work,

and one way of doing that has been to look at

stylistic similarities between the East Window, the documented window,

and other windows.

In York Minster, close similarities have been observed

in the St William Window, for example,

the giant window on the north side of the high altar.

But also in the city's parish churches, at All Saints, North Street,

that show some similarities to the style of John Thornton.

In the wide-eyed expressions, use of long noses, with bulbous tips.

The use of certain kinds of architectural canopies over figures.

And also in the technical sophistication of his work.

So, this has been tracked in the north of England,

-but it has also been found in the West Midlands.

-Right.

And a key monument for that is Great Malvern Priory in Worcestershire.

And especially the east window there...

..which shows many of the same characteristics

as those in the East Window and the St William Window at York.

So, there's a detective search going on in both the art,

trying to search for a style that can be ascribed to John Thornton,

and in the documents,

hunting him out in references in Coventry and in York.

But he remains somewhat an elusive figure, doesn't he?

He remains quite elusive, but it does appear that Thornton

was operating workshops both in York and in Coventry.

We have a sense of a business, if you like.

A great business operating across the North of England

and well down into the Midlands.

This is quite a remarkable thing for the 15th century.

If it were to be proved

that these windows are the work of John Thornton,

it would complete a picture that currently exists only on paper.

Here was a medieval superstar artist with the savvy

to market his talents across a great swathe of the country.

Whoever did create these windows was clearly a master of his craft,

and they become even more impressive

when you discover what was involved in actually making them,

because in John Thornton's time

producing even a single sheet of glass

was a skilled and labour-intensive process.

At this works in Birmingham,

they still use the same basic techniques

as glassmakers in the 15th century.

To produce a flat sheet of glass, you first have to make a cylinder.

Walter Pinches has been a glassmaker for more than 40 years.

What I'm doing now is a first-time gather.

This is to build up the amount of glass as I want.

-OK. So this is just clear glass at the moment?

-This is just clear glass at the moment.

-Right.

When Walter has gathered enough molten glass from the furnace,

he adds the colour, which nowadays is ready-made.

Medieval glassmakers would have added minerals to get the same result.

Once the colour has been evenly absorbed,

Walter can begin to shape the glass.

There's something of magic or alchemy about this whole process.

Just seeing the liquid glass come out of the furnace and then solidify,

and then as the air is being introduced as well,

it's just such an incredible process.

I can only imagine what it must have seemed like to the medieval viewer.

Wow, it's just ballooning in there, isn't it?

Then, as Walter begins to swing the balloon of molten glass,

the shape of the cylinder forms.

Over to the torch.

Over to the table.

-This is the finished cylinder.

-OK.

All's we have to do now is crack it off and put it in the oven.

That's incredible.

Finally, each cylinder is cut open

and flattened to make a square-edged pane.

Wow. So many stages, it's incredible.

-That's what makes it so expensive.

-Yeah.

A tremendous amount of work was involved in making a material

we nowadays take for granted.

And even that was only the first step

to crafting windows like these.

The skills that produced such finely detailed images have not been lost.

A few miles outside the City of York

is the studio of a contemporary stained-glass artist,

Helen Whittaker.

Helen creates her own original window designs by the same process

that John Thornton and his studio made the East Window.

So Helen, tell me what you're working on at the moment.

Where did you begin?

This is a design for a church in Northamptonshire.

This was a lovely brief, in that it was set by the church's flower guild.

I've got an arrangement of flowers associated with the seasons,

then this strong kind of cross,

which is hopefully going to be striking against this dark purple background.

So this is the first stage. This is called the vidimus.

So it starts with initial pencil sketches, then you develop it up to colour.

From that, you scale them up to full-size, and this is what's called a cartoon.

-I've also indicated the actual leads on there as well, by these black lines.

-Right.

So the cartoon really remains your point of reference for the painting and preparing the glass.

Yeah, very much so. It's key to the whole design.

So it's by tracing with paint that the design on paper

is transferred onto the individual pieces of glass.

So, Helen, what part of the process are we at now?

So this is how I go about glass painting.

I do the trace lines

and then I'll do what's called the shading, the matting, afterwards.

This glass is quite unusual in that it's called a flash glass.

You can see it's red, but it's actually two layers.

It's actually predominantly yellow with a flash of red on top.

What I've done here is taken away the red layer

to reveal the yellow underneath.

Is this something that would have happened in the medieval period?

It would have done,

but this would have been done probably by a pumice stone,

by some poor chap rubbing away for many hours.

Today, we're using acids, which eat away at the surface to reveal the yellow beneath.

Gives a lovely effect, doesn't it, the two types of glass?

-Yeah.

-So depending on how you apply the paint,

-you can get these different effects and textures?

-Yeah.

It's all about modulating the light, at the end of the day.

And then, once you've completed building up the paint...

There's the firing of the glass.

The pigments of the glass powder mixed with it.

What this does is, when you come to firing the glass, the glass is slightly tacky at that stage.

The pigment with the glass powder in it adheres to the surface so they bond together,

-making it permanent.

-Right.

Finally, the pieces of painted glass have to be assembled

and held in place with strips of lead.

So we had the leading process and it was soldered.

And here we have it, the finished piece,

ready, hopefully, to be fitted into the church.

It's absolutely beautiful.

I'm absolutely stunned by the finished product,

and seeing the way that it's got to this stage,

this collaborative artistic process

has made me appreciate stained glass all the more.

For the medieval church,

having these technical and artistic skills to hand

allowed for the creation of enormous narrative works of art

to instruct and inspire worshippers.

For us today, these are windows onto the medieval mind,

revealing how people thought about the Christian faith at the time.

And most revealing of all are the 81 panels of the East Window

depicting scenes from the Book of Revelation,

the Biblical prophecy of the end of the world

that became a popular obsession in the Middle Ages.

Revelation was written by Saint John of Patmos,

a first-century Christian who was persecuted for his faith

and exiled from Rome.

John foresees Christ's Second Coming at the End of Time,

when the Earth will be destroyed.

Good will triumph over evil.

And the dead will rise for the Last Judgment.

And when you hear them read today,

John's descriptions of these apocalyptic events

are still some of the most mesmerising passages

in all of the New Testament.

Now the seven angels who had the seven trumpets

made ready to blow them.

The first angel blew his trumpet and there followed hail and fire

mixed with blood which fell on the Earth,

and a third of the Earth was burnt up,

and a third of the trees were burnt up

and all green grass was burnt up.

The second angel blew his trumpet, and something like a great mountain,

burning with fire, was thrown into the sea,

and a third of the sea became blood,

a third of the living creatures in the sea died,

and a third of the ships were destroyed.

The third angel blew his trumpet and a great star fell from heaven,

blazing like a torch.

And it fell on a third of the rivers and on a fountain of water.

The name of the star is Wormwood.

A third of the waters became Wormwood.

And many men died of the water,

because it was made bitter.

Although Revelation is a book of prophecy,

it gives no clues as to exactly when the end of the world will come.

The great dread, of course, was that it might be imminent.

So Christians needed to be ready to have their souls judged by God.

The apocalypse became a hugely popular theme in medieval art,

and not only in the great cathedrals.

If you were sufficiently wealthy,

you might own an illuminated manuscript.

If you were not so well-off, you wouldn't have to look far

to find the same story on a church window or a wall.

I'm standing in the parish church of All Saint's North Street,

just a stone's throw from York Minster.

People grew up in these buildings. They were baptised,

married and buried with these stained-glass images

accompanying them through their lives.

And what do we find? Another version of the apocalypse.

The Pricke of Conscience window is one of those

thought to have been made by John Thornton's workshop,

shortly after the East Window in the Minster.

What makes it unique is the apocalypse story it depicts,

which comes not from the Bible, but from a 14th-century poem

written in Middle English, probably in Yorkshire.

Here, we see the last 15 days of the world,

when the seas will burn,

the land will be levelled by earthquakes

and, finally, all living things will die.

It was another terrible reminder to the medieval onlooker

that the destruction of the Earth and everything on it

was part of God's plan to save the faithful.

And only the faithful.

What the Pricke of Conscience window shows me is that stained glass

could communicate the same message in the same medium, about penitence,

salvation and the end of the world, but to different audiences.

Here, you see dramatic images

alongside vernacular inscriptions

in a verbal and visual language that everyone could understand.

Because the apocalypse is the single most important event

for all Christians.

So the East Window at York Minster

was part of a great medieval tradition of apocalypse narratives.

But the window presents the story in purely visual terms,

which is why it's so important

to preserve as many of the pictorial details as possible.

The conservation team at York Glaziers Trust

are hoping to have completed their work

on the 81 panels that tell the story of the apocalypse

within the next five years.

So what are the main differences that people will notice

once the panels are all restored?

Well, I think people will notice more glass. They'll see more glass.

The reason for that is that the gauge of lead we're using

is much finer.

It's more akin to the medieval, original lead.

We can then move on to use more modern techniques.

For example, adhesives.

So where a piece of glass is broken into a number of fragments,

we can edge-bond those pieces back together again,

and you can see the piece as it was intended to be seen.

The most sensitive part of the process involves the recreation

of pieces of painted glass that have been lost over the centuries.

We have an example here of the book.

You can see here the seals on the book.

So far, that piece has been repaired and bonded,

but we have this much missing.

You can't really tell what's happening here.

So, in rare cases like this,

we can actually paint in the missing piece.

-So this is a new piece of glass?

-That's right.

-Gosh, it's painted so beautifully. Wow!

-There's a new bit which fits

-into there like...

-Gosh!

you see exactly what's intended to be seen.

-Yes.

-The book is now very clear.

Once the pieces have been repaired in this way,

they can be re-assembled within a framework of new lead.

Tony Cattle will be responsible

for re-leading all the conserved panels.

Wow. So this is where it is all coming together.

Yeah. This is not the final stage,

but we're getting towards the end

-of the conservation, if you like.

-So you're putting in new leads.

We're putting in new leads all the way.

They've been completely re-leaded.

-And it looks like a proper painting now, doesn't it?

-It does, yeah.

That's the idea, really, to make it look like a proper painting

without noticing the lead so much.

-It's where art meets practicalities, isn't it?

-It is, yes.

-Because you've used the wider lead to outline the figures.

-Yeah.

That helps them stand out, but I suppose it's also to keep it strong.

Yeah, you do need some substance there, you know. Some strength.

-Is it very hard to do the leading on this?

-Not really, no.

-This piece is particularly easy. It's the angel's foot.

-Can I have a go?

-Yeah, sure.

-My goodness.

Wow, it feels so fragile.

-It has actually been bonded there.

-Yeah, be careful of the bond.

So what happens next?

Well, really you just need the lead

that you're going to use for that,

which is a 5mm piece.

-Then, to find the length you needed, you would stand it on one end.

-OK.

-And roll it round as if it was a ball.

-Like this?

-Yeah.

-And then go like that?

-Come back to that point there.

-OK, I understand.

-How's that?

-That's fine, yeah. Just a little bit bent.

So just a little bit, because it's got bends.

-What do I do now? I'd better put the glass down.

-Yeah.

-A sharp knife is...

-The most important tool?

-Yeah.

So, cut?

-Cut directly down.

-Like that?

-That's it.

Oh, wow. OK.

-And then we take the...

-You take the glass.

Looking at that, it wants to end at that point there.

-OK, so we need to give it a bit of an overlap, like that.

-Yeah.

And then slowly

-manipulate the lead to fit each.

-To fit into the facets.

Right in, because the next piece of glass will be going up to that edge.

My goodness. It's quite malleable once you work out the tension.

-Yes, it's quite soft.

-There you go.

-And around this turn.

-Bring it around that end.

-Oh, my goodness me.

-So just keep following the line?

-Keep following the shape of the glass, yeah.

And then try and get it back

-into position.

-Yep. Mm-hm.

Oh, my goodness. What an experience. Thank you.

-Wow.

-Just to finish it off,

really, you just need to put a nail in to hold it either side.

-Thank you for the opportunity.

-You're very welcome.

And for trusting me with such a fragile material!

Of course, this is only one panel.

There are 311 in the whole window. But it's a real privilege

to have been allowed to make even a tiny contribution

to such important work.

A project which, it is hoped, will transform

not just our experience of the East Window

but of the whole Minster.

CHORAL MUSIC

I wanted to get a sense of the atmosphere

when the building is being used as a place of worship,

which, after all, is its primary purpose.

And when you do that, you really appreciate just how affecting

the experience of light, space and sounds in a great cathedral can be,

for everyone involved.

If you say worship in a great cathedral is like theatre,

I'd have to say, yes, it is.

But of course it's not fiction, it's reality.

So when you have the daily acts

of worship happening here,

you do it in this setting of a great encounter

which is going on. And the encounter can be described

in all sorts of ways. It's heaven and earth,

it's time and eternity, it's mortality versus immortality,

it's humanity and God.

And they're brought together in this very carefully designed place.

And light is something

which is a real actor on the stage.

Light is the thing that pours through.

Light is the thing that is God.

So what do you anticipate will be the effect,

when the East Window's back in situ?

You'll be able to see much more what's going on

and that will be, in itself,

very important. Being able to read

a building like this is an art we want everyone to develop.

At one time, I guess a lot of people

would instinctively have known, because they knew the stories

of Genesis and the Old Testament and the Book of Revelation.

Now, in order to get on board with what's happening,

we'll be able to give them the right information

at the time they're looking at it.

This should increase their enjoyment of it enormously.

Then a new heaven and a new Earth,

for the first heaven and the first Earth had passed away

and the sea was no more.

And I saw the Holy City, New Jerusalem,

coming down out of heaven from God,

prepared as a bride adorned for her husband.

And I heard a loud voice from the throne

saying, "Behold, the dwelling of God is with men.

"He will dwell with them and they shall be his people

"and God himself will be with them.

"He will wipe away every tear from their eyes

"and death shall be no more.

"Neither shall there be mourning, nor crying,

"nor pain any more.

"for the former things have passed away."

And he who sat upon the throne

said, "Behold, I make all things new.

"I am the Alpha and the Omega,

"the beginning and the end."

Stained glass has been called the Poor Man's Bible,

and you only have to look at John Thornton's East Window to see why.

These panels gave people images to carry in their minds

together with the message they heard from the pulpit,

that they should strive to be one of the saved.

Of all the traditional visual arts, I think that stained glass

has a unique capacity

to communicate stories on a public scale.

But it can also illuminate changing attitudes across time.

To the medieval mind, the East Window was a portal

onto an eternal paradise after this fleeting life on Earth.

But now the light pouring through

these centuries-old images

affects us differently.

We've no trouble imagining back millions of years

to the birth of stars,

and yet our attitudes to life after death

are much more individual.

The window is no longer speaking to one community of people

with a common faith.

We all understand its message differently.

What was once a universal truth has become a question of choice.

So now, instead of looking through the glass,

we see in it a reflection of our own ideas and beliefs.

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