Caravaggio: Giovanni Battista (was the description in the museum at the time I took this picture).

From the Wikipedia: Since the 1970s art scholars and gender studies scholars have debated the homoeroticism of Caravaggio's art, but there is very little evidence from his own time regarding his sexuality. A connection with a certain Lena is mentioned in a 1605 court document (the complainant Pasqualone is speaking): "I didn't see who wounded me, but I never had disputes with anybody but the said Michelangelo (i.e., Caravaggio). A few nights ago he and I had words on the Corso on account of a girl called Lena who is to be found in Piazza Navona, past the palace of Mr. Sertorio Teofilo. She is Michelangelo's girl. Please, excuse me quickly, that I may dress my wounds." The biographer Passeri, however, writing about the incident some seventy years later, implies that although Lena was Caravaggio's friend and model there was no sexual relationship between them, and that Caravaggio was, on the contrary, taking revenge on Pasqualone for impugning his behaviour with her.

The sole other piece of evidence comes from the libel trial brought against Caravaggio by Baglione in 1603. Baglione accused Caravaggio and his friends of writing and distributing scurrilous doggerel attacking him; the pamphlets, according to Baglione's friend and witness Mao Salini, had been distributed by a certain Giovanni Battista, a bardassa, or boy prostitute, shared by Caravaggio and his friend Onorio Longhi. Caravaggio denied knowing any young boy of that name, and the allegation was not followed up.