A name in blood - Matt Rees

Italy, 1605: For the ruling Borgia family, Rome is a place of grand palazzos and frescoed cathedrals. For the lowly artist Caravaggio, it is a place of rough bars, knife fights, and grubby whores. Until he is commissioned to paint the Pope... Soon, Caravaggio has gained entry into the Borgia family's inner circle, and becomes the most celebrated artist in Rome. But when he falls for Lena, a low-born fruit-seller, and paints her into his Madonna series as a simple peasant woman, Italian society is outraged. Discredited as an artist, but unwilling to retract his vision of the woman he loves, Caravaggio is forced into a duel - and murders a nobleman.
Even his powerful patrons cannot protect him from a death sentence. So Caravaggio flees to Malta, where, before he can be pardoned, he must undergo the rigorous training of the Knights of Malta. His paintings continue to speak of his love for Lena. But before he can return to her, as a Knight and a noble, Caravaggio, the most famous artist in Italy - simply disappears...