Sometime between 1495 and 1496, Leonardo da Vinci painted one of Western art’s true masterpieces: The Last Supper. His then-patron, Ludovico Sforza, Duke of Milan, commissioned the work for the refectory of the Convent of Santa Maria delle Grazie. Ludovico had recently undertaken the building of the convent on the site of the Chapel of St. Mary of the Graces, built earlier by his father, Francesco.
Leonardo’s “canvas” for this work was huge by his standards. The Mona Lisa, for instance, is 30.2 x 20.9 inches. His previously largest painting, the unfinished Adoration of the Magi, is 94 x 98 inches. But you could hang almost any Leonardo canvas on any wall in your house – except The Last Supper, which is five yards tall by almost ten yards wide.
If only Leonardo had painted it on canvas!
But it’s a fresco. Painters of frescos work by laying down new lime plaster over stone walls and painting quickly with water-based powdered pigments that dry with the plaster: all fresh (fresco in Italian) ingredients. The damp plaster and the wet pigments dry together, integrated, and can be amazingly long-lived: on the Greek island of Santorini, there are still-visible Minoan frescos painted more than 3600 years ago.
Leonardo, always the innovator, decided to use tempera pigments mixed with oil for The Last Supper. He did this for several reasons: he wanted to get finer details and more vivid colors, and he wanted to work at his usual pace, which is to say slowly. Leonardo is famous for fussing. For instance, he probably began work on his portrait of Lisa Gherardini (Mona Lisa) in Florence, Italy in 1503 and had the painting with him, still unfinished, when he died in Amboise, France in 1519.
The trouble with Leonardo’s fresco technique is that, whereas it looked spectacular when completed, it began fading almost immediately. Today, only about 20 percent of the fresco remains visible, and it’s uncertain what’s left is salvageable. The convent is in a low-lying, damp area of Milan, and the refectory wall backed up against the kitchen with its constant heat and steam, and the dining area was lighted by candles – meaning candle smoke from would fill the room.
Three hundred years later, Napoleon’s troops, billeted in the convent, entertained themselves by pelting manure at the fresco, and during RAF bombing of Milan in WWII, the refectory roof was blown off, temporarily exposing The Last Supper to rain and dust.
Restoration efforts have helped preserve what remains, and the fresco is now in a climate-controlled room. Time-limited visits are permitted but require you to enter “through several pollution and humidity filtration chambers.” The thing is: the closer you get the worse it looks.
And we’ll never be able to see it as it looked when Leonardo first painted it. Or will we? I’ll answer that below. But first: the drama in the painting.
Leonardo does not portray the institution of the Eucharist, nor does he give us a charming tableau of fellowship around the Passover table in the Cenacle. He chose instead to illustrate the dramatic moment described in John 13: 21-30 when the Lord prophesies Judas’ betrayal. Leonardo captures the shock and bewilderment among the Apostles in the moments after Jesus has said, “Very truly, I tell you, one of you will betray me.”
As Matthew writes, “And they became greatly distressed and began to say to him one after another, ‘Surely not I, Lord?’” (26:17-30) That question is the same one Mark records. (14:12-25) Luke writes: “Then they began to ask one another which one of them it could be who would do this.” (22:7-23) But it’s John’s report that fired Leonardo’s imagination.
John writes, referring to himself: “One of his disciples – the one whom Jesus loved – was reclining next to him” – that “him” refers to Jesus – and “Simon Peter therefore motioned to him to ask Jesus of whom he was speaking.” This Leonardo catches exactly, foreshadowing the Passion.
As you look at the painting, from left to right the Apostles are Bartholomew, James the Less, Andrew, Peter, Judas, John, [the Lord], Thomas, James the Great, Philip, Matthew, Jude, and Simon. Leonardo has arranged them in trios.
The three on the left seem unsure they’ve heard aright, and James is reaching out to Peter, perhaps for clarification because Peter’s the one you’d ask. For his part, Peter leans behind Judas to ask John, since John is closest to Jesus, to ask the Lord for the identity of the betrayer. Thomas, the other James, and Philip all seem to be expressing one or another version of anxiety about their own possible guilt, and Matthew and Jude, may be asking Simon one of two questions: “Is it you?” – or – “What did the Lord say?”
Every one of them is in denial, with the possible exception of Judas, who clutches his money bag in his right hand and reaches out with his left to dip his finger in the bowl, just as Jesus does the same with His right hand.
Fortunately, few Renaissance painters worked alone. Leonardo himself was early in the employ (as a garzone or studio boy) of Andrea del Verrocchio, and by the time of The Last Supper, when da Vinci was in his late thirties, he had his own garzoni, some of whom doubtless worked with him at Santa Maria delle Grazie, and then tagged along during their master’s trip to France and, perhaps, the low countries.
And it was in Westerlo, Belgium, that one or more of da Vinci’s assistants, principally Andrea Solari, painted an exact replica of The Last Supper  for the Norbertine abbey at Tongerlo near Antwerp. It has even been suggested that Leonardo himself may have overseen the reproduction, which, thank heavens, was done in oil again, but this time on canvas. It remains today nearly as vivid as when it was completed in about 1520, the year after Leonardo’s death.