At a young age she was married first to Marcus Calpurnius Bibulus, her father's political ally. This marriage occurred between 58 BC and 53 BC. With him she had two children, at least one of them a son. Lucius Calpurnius Bibulus was possibly one of them although most modern historians believe Porcia was too young to have mothered Lucius, and that he was Bibulus' son by his previous marriage, as he was old enough to fight in the battle of Philippi in 42 BC. He died in 32 BC. It is possible that a son of Porcia and Bibulus was the man who wrote the biography of Brutus.