What does Biagio reveal about the Cavalier's story?

The Cavalier was born to their father's father by a woman none of them knew, but apparently enough in the man's affections for him to make him a lawyer and a Cavalier. He spent years of his life in an unknown Mohammedan country learning and practicing the science of hydraulics before he mysteriously fell into disgrace and was sold as a slave. From there, he was freed by the Venetians who discovered him rowing a slave ship, and he became a beggar in Venice. After being jailed for fighting, he was ransomed by the Baron and has lived as an authority-less authority among the family ever since.