His mother could possibly have been Porcia Catonis (daughter of Cato the Younger), although it is disputed, most likely he was a son by his father's first unknown wife.
[2][3] His two elder brothers were killed in Egypt by some of the soldiery which Aulus Gabinius had left there after having restored Ptolemy Auletes to the throne.
His father died in 48 BC from the exhaustion and strain of commanding the republican fleets against Caesar.
After Caesar's murder, Lucius chose the side of Marcus Junius Brutus, Porcia's new husband, for whom he fought at the battle of Philippi.
[2][3] After the defeat of Caesar's murderers, he surrendered to Marcus Antonius who later gave him command of his fleet.