The Senate had scheduled a meeting for March 15, purportedly for routine business, and the conspirators chose that date, known as the Ides of March, for an attack. They were able to recruit a few of Caesar’s close friends into the scheme, including Cassius brother in law, Marcus Brutus, by suggesting that Caesar was going to declare himself king on that day. In all, the conspiracy attracted about 60 people , with 20- all senators- to do the killing; the collective responsibility implicit in the act would allow them to transfer power to the Senate.
The tradition of the Ides of March notwithstanding, Caesar actually heeded personal premonitions and his wife’s advice to stay home that day (each had had disturbing dreams that night before.) but Cassius recruited a friend of Caesar’s to persuade him to come to the Senate meeting. As he left his house, someone we do not know who thrust a note into his hand. It went unread.
Caesar arrived at the Senate at around 11 AM. He almost immediately received a petition and as he read it, the senators crowed around him. At the signal, one of them grasped Caesar’s robe and pulled it down at the neck, and the designated first striker (a tribune of people named Casca) made poorly executed stab that barely grazed Caesar’s chest. But as Caesar tried to defend himself, he opened himself up to attach by others.