Gaius Julius Caesar was a Roman general and statesman. He played a critical role in the demise of the Roman Republic and the rise of the Roman Empire. He was a member of the First Triumvirate and led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war. Caesar subsequently became dictator from 49 BC until his assassination in 44 BC.

In 60 BC, Caesar, along with Crassus and Pompey, formed the First Triumvirate, a powerful political alliance. Caesar's military victories in the Gallic Wars greatly extended Roman territory and bolstered his political power. His achievements threatened the standing of Pompey, leading to a breakdown in their alliance. By 50 BC, Pompey had aligned himself with the Senate against Caesar.

Caesar defied the Senate by crossing the Rubicon in early January 49 BC, initiating Caesar's civil war, which he eventually won. Once in control, Caesar implemented significant reforms, including the creation of the Julian calendar, reducing the grain dole, settling veterans, expanding the Senate, and extending Roman citizenship.

By early 44 BC, Caesar was proclaimed "dictator for life", sparking fear among senators that he might become king. On the Ides of March (15 March) 44 BC, he was assassinated by a group of senators led by Brutus and Cassius. His death led to further civil wars, ultimately resulting in the establishment of the Roman Empire under his heir, Octavian, later known as Augustus.

Caesar was also an accomplished author and historian; much of his life is known through his own accounts of his military campaigns. He is considered one of history's greatest military commanders. His name "Caesar" became synonymous with "emperor" in the Roman Empire and influenced modern titles such as Kaiser and Tsar.