Caesars rise finished off a Republic that was weakening for the past 100 years. The aristocracy had been taking away the rights of the lower classes for years, and not Caesar was taking away the rights of the Aristocracy. Years of civil war had severely thinned the ranks of the Senate. Rather than refilling it with his natural enemies - the rich and powerful men of Rome - Caesar granted citizenship to the peoples of Hispania and Gaul and used their leaders to fill in the Senate. This meant that the senate was loyal to Caesar. In 44 BCE, they named him dictator for life.
The aristocracy, on March 15, assassinated Caesar on the Senate floor. The assassination was lead by his one time friend, Marcus Brutus. a direct descendent of Lucius Brutus, who overthrew the last king of Rome before the Republic was established 500 years before.