in 43 bc, after octavian received his consulship from the senate, one of his first actions was to have the people that had assassinated julius caesar declared murderers and enemies of the state. cicero, angry at octavian, wrote a letter to brutus explaining that the forces of octavian and mark antony were divided. antony had laid siege to the province of gaul, where he wanted the governorship. in response to this siege, octavian rallied his troops and fought a series of battles in which antony was defeated. upon hearing that neither antonius nor octavian had an army big enough to defend rome, brutus rallied his troops, which totalled about 17 legions.