There is evidence that Caesar had begun practical preparation for the campaign some time before late 45 BC . By 44 BC Caesar had begun a mass mobilization , sixteen legions ( c. 60,000 men ) and ten thousand cavalry were being gathered for the invasion . These would be supported by auxiliary cavalry and light armed infantry . Six of these legions had already been sent to Macedonia to train , along with a large sum of gold for the expedition . Octavius was sent to Apollonia ( within modern Albania ) , ostensibly as a student , to remain in contact with the army . As Caesar planned to be away for some time he reordered the senate and also insured that all magistrates , consuls , and tribunes would be appointed by him during his absence . Caesar intended to leave Rome to start the campaign on 18 March ; however , three days prior to his departure he was assassinated . The expedition was planned to take three years . It was to begin with a punitive attack on Dacia under King Burebista , who had been threatening Macedonia 's northern border . It has been suggested by Christopher Pelling that Dacia was going to be the expedition 's main target , not Parthia
assassinated
Assassination of Julius Caesar
Julius Caesar's planned invasion of the Parthian Empire