Giulia Farnese, played by (?), was called "La Bella Giulia" in her time because she was thought to be the most beautiful woman in Italy. She was not much older than Lucrezia.

The actress who plays her is indeed very beautiful--but is she the most beautiful woman in Italy?

More about the original Giulia--she was indeed captured by the French king (though Lucrezia was not with her). The pope was beside himself when this happened. And she was married to an Orsini, who was rumored to be an unacknowledged son of the pope (probably because he was good friends with Giulia's mother-in-law, who was therefore rumored to be an ex-mistress.)

The Farenese were an obscure family until one of them gave birth to the most beautiful woman in Italy. Naturally, the pope favored the family of his mistress. He made her brother a cardinal, and he later became pope himself. Now you can visit Farnese palaces and Farnese museums all over Italy. Ah, love.