The invading French troops at the start of the Second Italian War in 1499 had used Leonardo’s life-size clay model for the Gran Cavallo for target practice.

With Ludovico Sforza overthrown, Leonardo, with his assistant Salai and friend, the mathematician Luca Pacioli, flee Milan for Venice, where he is employed as a military architect and engineer, devising methods to defend the city from naval attack.

The Aldine Press publishes, in 1499, Francesco Colonna's illustrated book, Hypnerotomachia Poliphili (“The Strife of Love in a Dream”), a masterpiece of the twenty-five-year old art form.

In an elegant page layout, with refined woodcut illustrations in an Early Renaissance style, Hypnerotomachia Poliphili presents a mysterious arcane allegory in which Poliphilo pursues his love Polia through a dreamlike landscape, and is, seemingly, at last reconciled with her by the Fountain of Venus.

Colonna lived in Venice, and preached at St. Mark's Cathedral.

Besides Hypnerotomachia Poliphili, he definitely wrote an Italian epic poem called Delfili Somnium, the "Dream of Delfilo”, which goes unpublished in his lifetime and will not be published until 1959.

Colonna spends part of his life in the monastery of San Giovanni e Paolo in Venice, but the monastery is apparently not of the strictest observance and Colonna is granted leave to live outside its walls.