Answer: Julius Caesar (Gaius Julius Caesar) was a Roman military and political leader. He played a critical role in the transformation of the Roman Republic into the Roman Empire. During the late 60s and into the 50s BC, he formed political alliances that led to the so-called "First Triumvirate," an extra-legal arrangement with Marcus Licinius Crassus and Gnaeus Pompeius Magnus ("Pompey the Great") that was to dominate Roman politics for several years. Their factional attempts to amass power for themselves were opposed within the Roman Senate by the optimates, among them Marcus Porcius Cato and Marcus Calpurnius Bibulus, with the sometime support of Marcus Tullius Cicero. Caesar's conquest of Gaul extended the Roman world to the North Sea, and in 55 BC he also conducted the first Roman invasion of Britain. These achievements granted him unmatched military power and threatened to eclipse Pompey's, while the death of Crassus contributed to increasing political tensions between the two triumviral survivors. Political realignments in Rome finally led to a stand-off between Caesar and Pompey, the latter having taken up the cause of the Senate. With the order that sent his legions across the Rubicon, Caesar began a civil war in 49 BC from which he emerged as the unrivalled leader of the Roman world.
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