1453 - Leonardo da Vinci is born near Florence, Italy.

When he was twenty-four years old, Leonardo was arrested, along with several young companions, on the charge of sodomy.  No witnesses appeared against them and eventually the charges were dropped. It must be said that often anonymous charges like this were brought against people just for a nuisance. Renaissance Florentines didn't make the distinctions we make about sexuality today and apparently it was common for young men to get into sexual relationships; in fact, the word "Florenzer" was German slang for "homosexual". Leonardo had no relationships with women, never married, had no children, and raised many young protégés, including one nicknamed "Salai" which means "offspring of Satan", a sketch of whom is shown below. Salai stole things, broke things, lied, and was generally a, well, devil; if he were a mere student or servant he would have been fired. It's not hard to see how this imp would be attractive to Leonardo. He stayed with Leonardo for over twenty years, and appears many times in Leonardo's sketchbooks.
Leonardo's friend Machiavelli, the Florentine statesman who is famous for his advocacy of unscrupulous political opportunism, had a son, Ludovico, who apparently had a boyfriend. Machiavelli wrote to a friend to ask what he should do about it. The friend, who was Florence's ambassador to the Papal Court, replied:
"Since we are verging on old age, we might be severe and overly scrupulous, and we do not remember what we did as adolescents. So Ludovico has a boy with him, with whom he amuses himself, jests, takes, walks, growls in his ear, goes to bed together. What then? Even in these things perhaps there is nothing bad."

The second major implication of the sodomy case is, of course, the question of Leonardo's sexuality. Homosexuality was common in quatrocento Florence, and several things indicate that Leonardo was probably gay. He never married or showed any (recorded) interest in women; indeed, he wrote in his notebooks that male-female intercourse disgusted him. His anatomical drawings naturally include the sexual organs of both genders, but those of the male exhibit much more extensive attention. Finally, Leonardo surrounded himself with beautiful young male assistants, such as Salai and Melzi.