(lively piano music)
Voiceover: There are a handful of buildings
throughout history
that have changed the way we see architecture.
Voiceover: We're standing in one of them.
We're in Hagia Sophia in Istanbul.
What was once Constantinople.
Voiceover: Before that was Byzantium.
Voiceover: First it was a Greek city
then part of the Roman empire,
and then Constantine decided to found a city here.
Voiceover: Which he called the New Rome
and which came to be known as Constantinople.
Voiceover: Or the City of Constantine.
That happened right at the time
that Constantine was recognizing Christianity.
By the end of that century
Christianity would be become
the official religion of the Roman empire.
Voiceover: The emperor had his palace close by
and that was the reason
that the most important church was built here.
Now the church that we're standing in
is not that original church.
That burned down.
Voiceover: And so did the next church.
Voiceover: They were actually burned during riots
and the most famous riot took place in the 6th century
and it's called Nika Riot.
Voiceover: Against the emperor of the time, Justinian
and Justinian was the patron of this church.
Voiceover: This church was a way of putting to work
a lot of people in the city
that might otherwise riot,
but it was also a way for him to
express his power across the empire.
Voiceover: This was one of many churches
that Justinian built.
This building though is the centerpiece
of that building program.
Voiceover: It's unbelievable.
We're standing in this mountain of a building
and in fact, to use that kind of geologic term is
I think appropriate.
One author said that standing here
where we are in the sanctuary
was like standing at the bottom of an enormous canyon.
Now when this was built in the 6th century
it was absolutely unique in the world.
Not only for its scale, not only for its ambition,
but also for its design.
Voiceover: Justinian hired two theoreticians,
two scholars who were well-versed in geometry
and mathematical theory and physics
to think about how to vault this space.
The two churches that were here before
had wooden roofs.
Voiceover: Those were basic basilica structures.
A kind of architecture that the ancient Romans
were very comfortable with.
We see that kind of architecture
throughout the Roman empire,
and so it would have been very familiar
to the Roman emperors Constantine and Justinian.
Voiceover: Justinian asked his architects
to do something different,
and instead of building a traditional basilica
he had them build something that unified
a centrally planned space with a basilica space.
A basilica has a longitudinal format
and a centrally planned space
is based more on a circle.
Voiceover: Let's talk about the basic geometries here.
We have a dome that is phenomenally high.
If you think about how the Romans handled domes
and they did build very large dome structures.
Think about the pantheon in Rome
but in that case you have a round dome
sitting directly on a round barrel.
This building is doing something much different.
This dome is on a square
and so how in the world
do you put the base of a round dome
onto a square building?
Voiceover: From that square base
emerges two half domes forming a rectangle of space
that reminds us of a basilica.
Voiceover: How they've done it.
They've done it with something called the pendentive.
if you look at the base of the dome
you see that it comes down on a series of four arches
and a space between the four arches
and the base of the dome
it's kind of a triangle but it's curved.
This miraculous thing happens.
We know that dome must weigh an enormous amount
and yet it seems to come down
on the slenderest of points.
Voiceover: What the architects did was hide
the enormous stone piers
that are doing most of the work of supporting
the weight and the thrust of that dome.
Domes exert an enormous amount of pressure
not only down but also out.
Part of the work of supporting the dome
is also being done by the half domes on either side
and on the east end three smaller
half domes below that.
This is the first time we see
the dome on pendentives on this monumental scale.
Voiceover: It was dangerous.
It was incredible ambitious
but it didn't work perfectly at first.
Voiceover: No, there was an earthquake.
Part of the dome collapsed
and when it was rebuilt it was redesigned.
The dome that we see now is taller
than the dome that was here originally.
Voiceover: By making it steeper it allows
some of the lateral force to be reduced
so that the weight comes more vertically down.
The enormous thrust really did
destabilize the building,
and if you look carefully
you can actually see some columns
and other structural elements
have been pushed askew.
Voiceover: Here we are talking about the engineering.
Voiceover: This is an engineering marvel.
Voiceover: When you're inside the space
you don't think about that.
You think about the complexity of the space,
the mysteriousness of the space.
The way that the walls dissolve into light,
the mysticism of this space.
Voiceover: That's what this was all about.
In fact, an early chronicler said
it seems as if the dome is suspended from heaven
and part of the reason for that is
and this is just so incredibly ambitious.
The architects pierced the base of the dome
with 40 windows
so that lights streams in under the dome.
You begin to lose the structural elements
between the windows
and it seems almost to be continuous light.
Voiceover: Light in Byzantine thinking
is connected with ideas of perfection and the divine.
Voiceover: The windows create a rhythm
that almost sets the dome in motion
and then all of that is resting
on walls that are clad with marble
that have rich veins and patterns
that are all in motion.
The floor is made of huge paving stones
that seem as if it's almost a pattern of waves.
Voiceover: It lacks the solidity
of Ancient Roman architecture.
Here we have a new Christian architecture
for a new Christian Roman empire.
Voiceover: For me it is the perfect expression
of the transformation of the physical
into the spiritual.
This is a building that was
the spiritual heart of the empire.
Voiceover: The emperor in the east
in the Byzantine empire
which really was a continuation of he Roman empire
but with vast amounts of territories
that had been lost,
that emperor was not just a political figure,
he was also the head of the church.
He appointed the patriarch,
the man in charge of the church.
This is very different than
when we think about the pope
in the western part of the empire.
Voiceover: When important rites took place in this church
and the emperor and the patriarch came together
it was an expression of the unity
of heaven and earth.
Of political power and spiritual power.
We were talking about the way that this building
is an expression of mystery,
and its structural qualities are beautifully hidden.
One of the things that distracts our eye
from the structure is the surface decoration.
All of these upper surfaces
that are not colored stone
were covered with gold mosaic.
Voiceover: Mosaic that had decorative patterns.
Voiceover: Acanthus leaves, palm leaves.
You could find crosses everywhere.
What you couldn't find was mosaics
that showed figures.
This was a period in Byzantine history
that was leading up to what we call the iconoclasm.
Which was a point where
there was a real crisis of images.
When this church was built
it was a clear decision to avoid
any kind of figural imagery.
Voiceover: The decision might have been
because of concerns around the commandment
against creating raven images.
It also may have been to highlight the architecture
instead of drawing your attention to Mary or Christ,
but instead drawing your attention to
overall mystical effect of the space itself.
Voiceover: The color wasn't just from the mosaics.
All these clear glass was originally colored.
It was red, it was yellow,
it was purple, it was blue, it was green
and then you have the surface of the marbles.
Justinian payed an enormous amount of money
to import marbles from across his empire.
He's brought the most beautiful,
most elegant marbles that he could,
and he's embedded them in the walls,
what we call revetment and his workmen
were able to saw these pieces of marble crosswise
and then open them up like leaves of a book
so that the patterns were actually mirrors
creating this wonderful complex patterns.
You have light streaming in the windows,
gold mosaics, these colored marbles.
All of which created this kaleidoscope
of movement and energy.
Voiceover: When the emperor stood
with the patriarch of the orthodox church in this space
they wore gold and purple and silver.
Voiceover: There were gems embedded in the thrones.
There was an enormous screen
that protected the sanctuary
and by some accounts it was 35 feet high
completely covered in silver.
Voiceover: You had the laity, normal people like us
standing in the aisles and the galleries above,
and then only the patriarch, the priest, the clergy
and the emperor were allowed in this space
that as you said was screened.
You had a mystery within this mysterious space.
What a spectacle.
Voiceover: This building is almost 1500 years old
so it's gone through a lot of changes.
Voiceover: Change is visible all around us.
The floors are worn and uneven.
Parts of the marble revetment are lost
and they've been painted instead.
There's clearly mosaics
that date from different periods of time.
Most obviously there are Islamic inscriptions in the dome
from when this building was made into a mosque.
Voiceover: The Byzantine empire
was ultimately conquered by the Ottoman [Turks]
who were Muslims,
and this city, Constantinople was the great treasure
and the great gem in that city was this church.
When this city was conquered
one of the first things they did
was transform it into a mosque.
Voiceover: This functioned as a mosque until 1934
when it was secularized and made into a museum.
Voiceover: What we've lost mostly though
is all of the original Christian furnishings.
Voiceover: Not just furnishings but relics, reliquaries.
This was a space that was filled with holy objects.
Voiceover: The reason for this is not
when the Muslims invaded.
The reason for this is when
the Western European Christians invaded.
Voiceover: Right and that happened in 1204.
Voiceover: Instead of going to the Holy Land.
Voiceover: To take back the Holy Land from the Muslims.
Voiceover: The Crusaders owed the Venetians
a lot of money which they couldn't pay
and so they ended up sacking Constantinople instead.
Voiceover: A lot of the great treasures
that were once here are in Venice.
They're scattered through museums all over the world.
Voiceover: One can only imagine
how rich this space must have looked
when it was covered with gold and silver,
when there were gems studding
its most important furniture.
Voiceover: When people were venerating the relics
that were here and the icons that were here.
Voiceover: When this was the center of the empire.
(lively piano music)