Many of those who took part in the assassination of Caesar
was formerly ardent supporters of Pompey and had fought at Pharsalus.<ref> Jiménez, Ramon L. <i>Caesar Against Rome: The Great Roman Civil War</i> (New York, Praeger, 2006), p. 117</ref> However, the dread of monarchy was so ingrained in the minds of the Roman elite that it was more powerful than gratitude and even personal feelings. Cassius the prime mover of the conspiracy was able to present the assassination of the victor of Pharsalus as tyrannicide, the killing of a tyrant. This persuaded many including Brutus to join the plot as they saw it as their duty as Romans. However, the evidence that Caesar wanted a return to monarchy is scanty and not conclusive. Whatever his intentions, it is clear that the conspirators believed that he was determined to rule as king.<ref> Holland, Tom, <i>Rubicon: The Last Years of the Roman Republic</i> (London, Anchor Books, 2003), p 189</ref>
====Breakdown in relations with the Senate====
While the apparent pretensions of Caesar angered many of the conspirators, others were angered over his apparent lack of respect for Roman senators. Several of the conspirators were linked to senators, and the plotters believed that they were acting in the name of the Senate. Senators were technically the lawmakers and the ultimate source of authority in the Republic.<ref>Holland, p. 197</ref> However, Caesar treated that body in a high-handed manner and often with contempt. He did not act in a respectful manner towards the Senate and this alienated many of them.
Many senators saw his dismissive behavior as an affront and believed this was a thinly veiled attempt effort to marginalize the Senate. They saw his actions as overt attempt to subvert the traditional form of government. Moreover, during the civil wars when Mark Anthony had governed Italy, the Senate had been cowed into submission by him. Many senators yearned for a return to the days when it was the main decision-making body in the Republic.
Caesar was an incredibly divisive figure in Rome.
He was genuinely loved by the most Romans, but despised by the City's elite. The senatorial class and their adherents were very suspicious and hated Caesar. He was a member of the popular party and related by marriage to Marius, the darling of the common people. Moreover, many hated Caesar for personal reasons, and vengeance was almost certainly a factor in the assassination on the Ides of March. <ref> Holland, p 201</ref>
He had killed many of the senatorial order and the Roman elite during the civil wars. Friends and family members of the elite had died on many battlefields against Caesar during the civil war. Many prominent and revered Romans such as Cato had committed suicide to escape having to live in a Rome dominated by one man. Moreover, Caesar's policy of clemency did not reconcile the elite to him and his regime. Those whom he had pardoned after his victories continued to resent him and were instrumental in his assassination. Mercy was a characteristic of a king or a tyrant and those who accepted it was thought to have been dishonored.<ref>Holland, p 210</ref> Furthermore, in the social system of the time, Senators had become dependent on Caesar. Ultimately Cassius and Brutus, while pardoned by Caesar, were eager to wipe away the stain on their honor that they only lived due to the mercy of a despised autocratic ruler.