Cardinal Francesco Della Rovere was elected Pope by colleagues who believed he was an unworldly mystic who could be easily controlled. They were right about his being a mystic, wrong about all else. In some deep sense, Sixtus believes he IS God and that whatever he does in God’s name is justified.

Unlike his “nephew” Riario, who can focus on long term strategic success, Sixtus “feels each sparrow fall” and violently resents any frustration of his will, and is capable of, and likely to take, violent revenge – even if it harms his long term interests.

Sixtus’ goals are to shore up the Church's spiritual authority, increase its wealth, and to end seven hundred years of Muslim expansion. To this end, Sixtus is rebuilding the Vatican, Rome and the Church itself. Initially, Sixtus regards Da Vinci as a distraction. Then, as an enemy whose insults must be avenged. Eventually, Sixtus comes to view Da Vinci as Riario does: a prize sent from Heaven, to be brought under Rome’s yoke.[