The Companions (Greek: ἑταῖροι, hetairoi) were the elite cavalry of the Macedonian army from the time of king Philip II of Macedon and achieved their greatest prestige under Alexander the Great, and have been regarded as the best cavalry in the ancient world and the first shock cavalry. Chosen Companions/Hetairoi formed the elite guard of the king (Somatophylakes).
The assassination of Julius Caesar was the result of a conspiracy by many Roman senators who called themselves Liberators. Led by Gaius Cassius Longinus and Marcus Junius Brutus, they stabbed Julius Caesar to death in a location adjacent to the Theatre of Pompey on the Ides of March (March 15), 44 BCE. The ramifications of the assassination led to the Liberators' civil war and, ultimately, to the Principate period of the Roman Empire.