Julius Caesar, born in July of 100 BC, is remembered as a successful general and a Roman dictator who was assassinated in 44 BC for becoming too powerful. True, he had constantly worked to increase and maintain his power inside and outside Rome, and bypassed the law that consuls rule for one year only. He was nevertheless very popular with the Roman people and rule was divided in the Second Triumvirate, comprised of three of his chief allies (Octavian, Mark Antony and Lepidus), who reigned together until Antony and Octavian fell out and Lepidus was stripped of power.
Caesar was greedy for power, and changed laws to benefit himself, but he was not the first to do so. Marius and Sulla, years before, had also both secured followers and seized supreme power; Sulla even attacked Rome. It seems that Roman territory was effectively an empire long before it became one in name, with a single, autocratic government and rule extended through aggressive military action.