Marcus Junius Brutus was a Roman senator and one of the key conspirators in the assassination of Julius Caesar in 44 BC. He was known for his role in the plot to overthrow Caesar, whom he saw as a threat to the Roman Republic. Brutus was also a supporter of the republican cause and believed in the principles of liberty and democracy. His involvement in the assassination had a significant impact on Roman history and led to a series of civil wars and the eventual rise of the Roman Empire.