A member of the First Triumvirate , Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war , and subsequently became dictator from 49 BC until his assassination in 44 BC.
He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire. Their attempts to amass political power were opposed by many in the Senate , among them Cato the Younger with the private support of Cicero.
Caesar rose to become one of the most powerful politicians in the Roman Republic through a string of military victories in the Gallic Wars , completed by 51 BC, which greatly extended Roman territory. During this time he both invaded Britain and built a bridge across the river Rhine.
These achievements and the support of his veteran army threatened to eclipse the standing of Pompey, who had realigned himself with the Senate after the death of Crassus in 53 BC. With the Gallic Wars concluded, the Senate ordered Caesar to step down from his military command and return to Rome. In 49 BC, Caesar openly defied the Senate's authority by crossing the Rubicon and marching towards Rome at the head of an army.
After assuming control of government, Caesar began a programme of social and governmental reform, including the creation of the Julian calendar. He gave citizenship to many residents of far regions of the Roman Republic.
