The Secret Supper's main characters are described below. Those whose names are followed by dates of birth and death are actual historical figures who also appear as characters in the novel.

Alberti, Father León Battista (1404-1472). Besides being a priest, he was a painter, architect, poet, antiquarian, philosopher, and inventor. But he was also famous in the art of encrypting messages, designing the first cryptograph in history: a "coding disk" that facilitated the encrypting  and deciphering of secret messages.

Alexander VI, Pope (1431-1503). Of Spanish origin, he was one of the most complex figures of his time. He purchased his accession to the throne of Peter, and his corrupt and dissolute life earned him numerous enemies. He had five sons. And surprisingly, he believed himself a descendent of the Egyptian god Osiris.

Amadeo of Portugal (1430-1482). This Franciscan, whose lay name was João Mendes da Silva, was born in Ceuta, Spain, the brother of Saint Beatriz da Silva, and died under suspicion of heresy.  He wrote Apocalipsis Nova, a treatise that inspired Leonardo for his Virgin of the Rocks. Amadeo's text also prophesied the coming of an angelic pope.

Arno, Brother Guglielmo. Responsible for the meals served at the monastery of Santa Maria delle Grazie; "infected" with the Cathar heresy.

Bacon, Brother Roger (1214-1294).  A member of the Franciscan order, an inventor, theologian, and philosopher. Author of the treatise De Secretis Artis et Naturae Operibus, which explains twelve distinct forms of hiding a message in a work of art. In effect, this was the first European book that described the use of cryptography. Many consider Bacon a kind of "Leonardo'" of the 13th century.

Bandello, Brother Matteo (1484-1561). He was only twelve years old when Leonardo painted The Last Supper. He was a cousin of Father Prior Vicenzo Bandello and became the most celebrated novelist of the Italian Renaissance. In his writings he spoke of his childhood in the company of Leonardo.

Bandello, Father Prior Vicenzo (1435-1506). Prior of the monastery of Santa Maria delle Grazie in Milan between 1495 and 1501. After his term in that office and the death of Father Gioacchino Torriani, he was named Master General of the Order of Saint Dominic.

Benedetto, Brother. A Dominican at Santa Maria delle Grazie, confessor and secretary to Father Prior Bandello. He lost his eye at seventeen years of age from an assault at the monastery of Castelnuovo. Following this event he was transferred to the convent of Santa Maria delle Grazie.

Botticelli, Sandro (1444-1510). He was, like Leonardo, a disciple of Verrocchio, although also of Fra Filippo Lippi. He is considered one of the great geniuses of the Italian Renaissance. Thanks to the Medici, he studied pagan themes and applied this knowledge to works like Spring and The Birth of Venus. For a time, he used his painting as an instrument of magic on behalf of his protector. Under the influence of the heretical monk Savonarola he abandoned painting.

Cosimo the Elder (1389-1464), also known as Cosimo de Medici.  Governor of Florence and famous merchant, he was the great patron of intellectuals and artists of his time. After the Council of Florence, in 1431, that attempted to unite Eastern and Western Christianity, he founded the Platonic Academy, which he promptly entrusted to the then extremely young Marsilio Ficino.

Crivelli, Elena. Daughter of Lucrezia and Carlo Crivelli, the celebrated Italian painter of the 15th century. In the novel she is presented as the descendent of a line of women initiated in the secrets of Mary Magdalene.

Crivelli, Lucrezia (1452-1519). She was the model Leonardo used for La Bella Ferronière (today in the Louvre, in Paris). As one of the mistresses of Ludovico Sforza, she bore him at least one daughter out of wedlock.

da Benascio, Sister Veronica (1445-1497). Augustinian nun from the Milanese convent of Santa Marta; later beatified. Her life was filled with visions and ecstasies, and her divinations caused a sensation during her epoch. She actually admonished Pope Alexander for his profligate ways. She correctly predicted she would die on Friday, January 13, 1497.

d’Este, Beatrice (1475-1497). Duchess of Milan, daughter of the Duke of Ferrara and wife of the Milanese Ludovico Sforza. Her lifelong obsession was to convert Milan into a new Athens that would restore humanity to the "Golden Age" about which the ancient philosophers had spoken. She lived surrounded by luxury and fashion until her death during childbirth, in January 1497.  She incarnated the Italian ideal of the Renaissance Princess.

de Viterbo, Annio (1432-1502). A Dominican friar, professor of theology and expert in Oriental languages. Alexander VI named him Master of the Holy Palace and he died probably from poisoning. Author of various books, he was the first "archeologist" of history, although he was also one of the great falsifiers of his time. He fabricated Egyptian pieces to which he added spurious inscriptions to justify his theories. Today he is practically forgotten.

d’Oggiono, Marco (1470-1549). He became one of Leonardo da Vinci’s favorite students, remarkable for his talent at painting frescoes. After witnessing the completion of The Last Supper, at Santa Maria delle Grazie, he was one of the artists to copy it most.

della Mirandola, Pico (1463-1494). He was one of the most fervent disciples of Plato in the Renaissance. His teacher was Marsilio Ficino, by whose hand he learned Hebrew and was introduced to the Cabala. Although the Pope banned the reading of his books, he absolved him in 1493.

Ficino, Marsilio (1433-1499). Outstanding intellectual, doctor, musician, and preacher of his time.  He translated into Latin for the first time the works of Plato and the treatises on magic of the Egyptians known as the Corpus Hermeticum. He founded the Academy of Florence, from which the Renaissance was "born."

Forzetta, Mario. Painter’s apprentice, born (like Beatrice d’Este) in Ferrara. At seventeen, he traveled to Milan to work in the bottega of Leonardo da Vinci. However, he soon ended up trafficking in ancient manuscripts in the service of Oliverio Jacaranda. It was in his native Ferrara that he entered into contact with the Cathar heresy.

Giberto, Brother. Sacristan at Santa Maria delle Grazie. He was born on the frontier of the Germanic Empire. His pumpkin-colored hair made him the butt of not a few jibes in his community.

Jacaranda, Oliverio. Antiquarian, originally from Valencia, Spain, as was Pope Alexander VI. He was one of the first antiquarians to furnish the pontifical palaces, as well as the Sforza family, with ancient works of art.

Leonardo da Vinci (1452-1519). Embodied the ideal of the Renaissance man. Painter, sculptor, scientist, engineer, cook and musician, he bequeathed to posterity more than 13,000 pages of notes, a few paintings, and an enigmatic, finished mural known as The Last Supper. His contemporaries considered him a bad Christian, and the Pope never called upon him to decorate any Vatican building. Nevertheless, until the publication of this novel, no one seems to have understood very well what exactly Leonardo’s beliefs were

Leyre, Father Agostino. Inquisitor from Rome and important member of the Secretariat of Keys of the Pontifical States.  Expert in cryptography and theology. He narrates the story as an old man, from his retreat in Egypt, the place to which he fled following the discoveries he made in Milan during his mission to spy on Leonardo da Vinci in the winter of 1497.

Lorenzo the Magnificent (1449-1492), also known as Lorenzo de Medici. Grandson of Cosimo the Elder, he was also an impassioned patron of the arts. He maintained Marsilio Ficino as head of the Platonic Academy and was also Michelangelo’s benefactor.  He was particularly interested in ancient manuscripts, numismatics, and stone engravings.

Luini, Bernardino (1470-1532). Important disciple of Leonardo da Vinci whose works may be seen in various important European museums. Little biographical information about him survives, but he seems never to have left the area of Italian Lombardy.

Pinturicchio (1454-1513). His real name was Bernardino di Betto. His intellectual formation took place at the Academy of Marsilio Ficino. In 1493 he was called to Rome to decorate the Borgia apartments, by order of Pope Alexander VI.  Under instructions from Annio de Viterbo, Pinturicchio re-created the myth of the Egyptian gods Osiris, Isis and Apis, depicting for the first time sacred oxen, pyramids, and pagan divinities in the heart of the papacy.

Plato (428-347 B.C.). This father of Western philosophy lay forgotten until the 15th century, when his works were translated by Marsilio Ficino and printed for the first time in  Italy in  1483. To impart his knowledge, Plato founded the Academy, an institution that Ficino would try to imitate nineteen centuries later with the assistance of the Medici family.

Ponte, Fabio. Personal secretary to Annio de Viterbo and cousin of the Master General of the Dominicans, Gioacchino Torriani.

Savonarola, Girolamo (1452-1498). This Dominican, born in Ferrara, was one of the most polemical figures of his time. He preached against the wealth of the papacy and managed even to convince artists like Botticelli to burn their works that employed pagan motifs. His influential enemies eventually had him hanged and burned at the stake for heresy.

Sforza, Brother Mauro. Cousin to the Duke of Milan, he entered the monastery of Santa Maria delle Grazie after the death of his uncle Gian Galeazzo Sforza, in 1494. He worked as a sexton.

Sforza, Ludovico (1452-1508), also known as Ludovico il Moro (i.e., the Moor), because of his dark skin. Duke of Milan, patron of Leonardo da Vinci and responsible for the project of The Last Supper in the monastery of Santa Maria delle Grazie.  He commissioned this fresco as part of his project to convert the monastery into his family mausoleum.

Torriani, Master General Gioacchino (1417-1500). Highest authority of the Order of Saint Dominic, he was a man of great culture and one of the first humanists of the Renaissance. He spoke five languages.

Toscanelli, Paolo (1398-1482). Italian scientist, cartographer, and geographer who inspired the voyages of Columbus to America.   His studies contributed to the knowledge of astronomy in his time, and he constructed a sundial for the Cathedral of Florence, described in the novel.

Trivulzio, Father Alessandro. Native of Riccio, he was the librarian at Santa Maria delle Grazie. Devoted to the study of ancient manuscripts, he assembled an important collection for the monastery.