Vittore Carpaccio
St. Thomas Aquinas with SS. Marc and Louis of Toulouse

The altarpiece is more than two and a half metres high and almost two metres wide. The intense colours are applied to poplar wood. The painting has been in the possession of the Staatsgalerie Stuttgart since 1852.

The portrait format shows three men and a kneeling boy of about twelve under a cloudy sky with Mary and the Christ Child. 

The heavenly scene takes up the upper third of the picture, which ends in an arch at the top. Surrounded by a golden glow, the Virgin holds her naked son in her arms. He looks down, his right hand raised in blessing. Angels hover around them. Only their heads and wings emerge from the grey-blue clouds. Below them, four angels with larger wings stretch a narrow red cloth across the picture, which separates heaven from the earthly events in the lower part of the painting. 

The three men and the boy occupy this lower part. The group is in a room with two arched windows looking out onto a hilly landscape with a mountain range in the background. Between the windows, in the centre of the picture, one of the men is enthroned on a pedestal. He is wearing a white robe with a black cloak and a hooded cloak over it. The monk, St. Thomas Aquinas, sits behind a lectern on which lies a thick, open book. His left hand rests on it, while his right hand is raised. His extended forefinger points upwards to the sky. 

The knee-high pedestal has two doors. The left one is wide open, the right one, half closed, has a key in it. Another key hangs from it. Inside the pedestal is a pile of books. 

To the left of Thomas Aquinas is a man with a dark full beard, St. Mark. He is wearing a long red robe with many folds. A blue-green cloth is wrapped around his shoulders and hips. His bare feet are in sandals. The Saint is holding an open book and is looking intently at the man to his right. 

The man on the right, St. Louis of Toulouse, wears a mitre and a red and gold patterned mantle over a white robe with red trim that falls over his feet. He holds a crozier in his left hand and an open book in his right. The Bishop shows the printed pages to St. Mark. To the right of Louis of Toulouse, at the feet of Thomas Aquinas, kneels the boy in a blue fur-lined cloak. He is depicted in the manner of a founder's portrait, with his arms folded across his chest and looking up at St. Thomas Aquinas. 

On the floor, in the centre of the lower edge of the picture, there is a painted note with the artist's signature and the date in Latin.

Three saints engaged in conversation. On the far left stands Saint Mark – the patron saint of the city of Venice. In the centre, St Thomas Aquinas sits enthroned at a writing desk, with the son of the altarpiece's donor kneeling at his feet. And on the right is Saint Louis of Toulouse wearing the regalia of a bishop. 

You're probably wondering what these figures have in common. From a theological point of view, not very much. They lived at different times, so they could never have met. But they share the given names of an important Venetian family – the Dragans. Tommaso Dragan and his brother-in-law Marco were from a generation that had revolutionised glass-making. In the late 15th century, new manufacturing techniques and the importation of high-quality raw materials across long distances meant the local glassworks could now produce especially high-quality, pure white glass – a luxury product known as crystal glass, or simply crystal.

That's actually referenced on the page of the bible Louis is holding. It's from the Book of Revelation: 

"Then he showed me a river of the water of life, clear as crystal, coming from the throne of God and of the Lamb."

However, when Carpaccio delivered the altarpiece as per his client's order, there was probably a minor upset. Take a look at the clouds moving in front of St Thomas's throne-cum-desk and forming a second level to the composition: The angels holding a length of red cloth and the two red putti heads appear to be later additions to the altarpiece... And indeed: a recent examination using infrared photography revealed an underdrawing. That infrared photograph is on display as the second image at this stop. Above the heads of Saint Mark and Saint Louis, you can see an architectural feature with an arch and round panes of glass, what's known as bull's-eye panes. That was the kind of glazing used in windows at the time.

Carpaccio had obviously misunderstood. The up-and-coming Dragan family hadn't made its fortune by producing commonplace bull's-eye panes, but by making gilded and enamelled crystal glass vessels! The Dragans were presumably outraged, rejected the painting and forced Carpaccio to hurry up and rework it.

The piece of music selected to accompany this altarpiece is by Alexander Demophon Venetus, and it addresses the Virgin Mary directly: "Volgi gli occhi, o madre pia" – "Turn your eyes, O pious mother". If you'd like to listen to the whole piece, you can access it on the second player.

In this picture you can see three saints. On the left is Saint Mark, the patron saint of Venice. In the middle sits Saint Thomas Aquinas, and on the bottom right a child with long hair is kneeling. On the right is Saint Louis of Toulouse, wearing the clothes of a bishop.

The three saints do not have much in common. They lived at different times and therefore could not have met. But the three bear the first names of men from the family that commissioned and paid for the picture – Tommaso (Thomas) and Marco (Mark) from the Dragan family.

The Dragan family was very rich and important. They had invented a new way of making glass and were able to use it to produce particularly valuable crystal glass. Crystal glass was a luxury product at the time that only rich people could afford. Louis, on the right, is holding a piece of paper with a relevant Bible passage in his hand:

"Then he showed me a river of the water of life, clear as crystal, coming from the throne of God and of the Lamb."

But the painting tells another story: When Carpaccio showed the painting to the Dragan family for the first time, there was probably an incident. Carpaccio had painted a window with round panes of glass. These panes of glass are called bull's-eye panes. Bull's-eye pans were common and easy to make at the time.

But Carpaccio must have been mistaken: The Dragan family did not make bull's-eye pans, but gilded crystal vessels. Today it is assumed that the Dragan family rejected the painting and asked Carpaccio to paint over the bull's-eye panes.

You can see how he did it here: The angels holding the red ribbon and the small red angel heads further back were painted later. We know about this misunderstanding today because the bull's-eye panes were rediscovered by an infrared examination.