Question

why was julious ceaser killed

Answer 1

He was assassinated by the Cassius led faction that was against him. This faction did not want him to become the Roman King. Cassius hatched a conspiracy against him in which he convinced the fellow conspirators that he was an ambitious person and did not deserve to become the King. So they made a cunning plot and stabbed him to death.  

Answer 2

Caesar was killed for three reasons: First, the conspirators wanted to halt his power growth. Second, they tried to prevent him from becoming king and destroying the Roman Republic. The assassination of Julius Caesar ultimately started a civil war that ended with the destruction of the Roman republic.