[5] In 42, after the founding of the second Triumvirate, Saxa was, together with Gaius Norbanus Flaccus, appointed by Mark Antony to lead the advance force of eight legions into Thrace before the Battle of Philippi.
[6] Saxa later went on to be appointed governor of Syria by Antony in 41 BC while Norbanus was elected consul in 38, recognizing the great prestige of the victory over the liberatores.
He was heavily defeated near Antioch, when Quintus Labienus led a Parthian intervention of Syria in 40 BC.
The eagle standards were returned together with those captured in 53 BC from Marcus Licinius Crassus, a great propaganda victory for Rome.
A brother of Decidius Saxa was his Quaestor in Syria in 40 BC and fought with him against the Parthians, but his soldiers deserted to the enemy so that he had to surrender to Quintus Labienus.