This leader's general Trebonius led a siege against the city of Massilia. This leader's plan to besiege   an enemy against the sea was thwarted when two defectors told his enemy about the gaps in his walls,  leading to this leader's retreat from Dyrrhachium. He used a hidden fourth regiment of infantry to   turn the enemy's left flank and win the Battle of Pharsalus, after which this leader fought Ptolemy  the Thirteenth alongside Cleopatra. Name this Roman leader who 
This leader's general Trebonius led a siege against the city of Massilia. This leader's plan to besiege   an enemy against the sea was thwarted when two defectors told his enemy about the gaps in his walls,  leading to this leader's retreat from Dyrrhachium. He used a hidden fourth regiment of infantry to   turn the enemy's left flank and win the Battle of Pharsalus, after which this leader fought Ptolemy  the Thirteenth alongside Cleopatra. Name this Roman leader who began a civil war against Pompey  after crossing the Rubicon, and was eventually assassinated by Cassius and Brutus in 44 BCE on the  Ides of March.
This leader's general Trebonius led a siege against the city of Massilia.