Who is Marcus Brutus from Plutarch's Lives, Volume 2 and what is their importance?

Marcus Brutus was a wealthy Roman senator. He first sided with Pompey against Caesar in the civil war but returned to Caesar after Pompey's defeat. Brutus believed that Caesar had become too powerful and was one of the Senators who planned and participated in assassination in the Senate. After taking part in the assassination, Brutus fled Rome and raised an army. He was defeated and committed suicide.