Leonardo da Vinci's painting on this subject is fairly interesting to look at and contains many subtle details that escape the notice of most people, as they simply see the typical religious scene. These details are somewhat disturbing and express somewhat heretical points of view. All references to the painting in this writeup are with the figure of Jesus at the center of the painting as reference, to avoid any confusion.

  • Seated to the right of Jesus, turned away from him, is an unmistakably feminine figure. Commentators explain this away as being the disciple John (who is said to be very young), but note the very feminine bodice and facial features of the figure.
  • This female figure forms a letter "M" with Christ. To some commentators, this would indicate that the female figure is actually Mary Magdalene.
  • A hand that cannot possibly belong to anyone visible at the table cuts across the female figure's neck.
  • The sixth figure from the left of Jesus (the second figure from the left edge of the painting, in profile), looks almost exactly like Jesus himself. He is even dressed identically, the only difference is that the "real" Jesus has his robe draped on his left shoulder.
  • There is a hand holding a dagger, positioned in such a way as to not belong to any of the figures on the table, pointed threateningly at the third person at the right side of Jesus.
  • The first figure on Jesus' left side is raising his finger upwards in an expression that characterized John the Baptist in many of Leonardo's other works (e.g. his 1513-16 painting and his sculpture). From his facial expression it seems as if this figure is urging Jesus to remember John.
  • The fifth figure on Jesus's left, turned away and with a disdainful expression, looks remarkably like Leonardo himself, as though he were expressing his own disdain for Jesus Christ.
  • There does not seem to be any wine on the table, only bread apparently. It may seem like a minor quibble but the fact is both the bread and the wine were a major feature of the Last Supper. Not displaying "the blood of the new and everlasting covenant" that would be "shed for you and for all men so that sins may be forgiven" which is what the wine is supposed to symbolize is an attempt to minimize or nullify that symbolism.

These kinds of inconsistencies point to the fact that Leonardo may have been versed in a secret heretical tradition, perhaps the Mandaean heresy that believed Jesus to be an impostor who usurped the messiahship from John the Baptist. He may well have accepted the commission to produce such a patently Christian work as a means to secretly slip in some subversive doctrines to those who would take the time to look beyond the religious scene into what the painting really depicted. It would have been his joke on the exoteric power that suppressed his esoteric beliefs.

It could be a just mere coincidence if these inconsistencies appear in only one work, but in fact they are also present in one of the two "Virgin of the Rocks" paintings he made (the one made from 1483-1486 and is now at the Louvre), which had been the subject of a long-running legal dispute between Leonardo and the monastery that commissioned the work. Another work that displays the same kind of suspiciously heretical ideas is his "Adoration of the Magi" (1481-1482).

These strange facts about Leonardo's paintings are among the subject matter of Lynn Picknett and Clive Prince's book The Templar Revelation, which gives a somewhat different account of the Prieure de Sion from that presented in Holy Blood, Holy Grail.