In Game Bio:
Date of Birth: 1460.
The child of an unknown Venetian nobleman and a prostitute, Rosa grew up on her own in the streets of Venice. In 1475, she attempted to pickpocket the leader of the Venetian Thieves Guild and was caught red-handed. But, Antonio, instead of reporting her to the police, took her on as a pupil.
He kept several logs of her training, noting that her ability to leap up from the street to seemingly unreachable windowsills "was unprecedented".
In terms of social skills, her vocabulary was "colourful to say the least". Apparently, she could also hold her own in a fight. Antonio writes that "the last of my thieves who tried to kiss her escaped with most of his mouth intact".