Et Tu Brute?

There is a common misperception that Marcus Junius Brutus was the sole or even the chief assassin of Gaius Julius Caeser. In addition, Brutus was reputed to be a personal traitor, having been a friend of Caeser's. This common representation does not mesh with the known facts.
The tyrranicide of Julius Caeser was primarily conceived and carried out by Publius Servilius Casca. Casca was the first to stab Caeser.
Approaching Caeser, the "dictator for life," Casca made a reached out to grasp the hands of Caeser in a gesture of respect and affection. Instead, Casca firmly held onto Caeser, pulling his body close, and eventually stabbing him in the neck.
The other Senators gathered around the stumbling Caeser, and stabbed him in total more than twenty times.
Brutus, appointed by Caeser as the governor of Gaul, was not Caeser's trusted friend. Instead, Brutus held the role of a political affiliate. Brutus came from an old patrician family, and as such added much cachet to Caeser's political reputation. Brutus was certainly in a position to add some refinement to the more coarse personality of Caeser.
In William Shakespeare's play "Julius Caeser" Caeser declares "Et tu Brute" in response to the betrayal of Brutus. In fact, Caeser is accredited with declaring in Greek "Even you my child?" which, from the known background of both men, appears to reveal the mentor characteristic of their relationship.

FOr more information on Julius Caeser, check out Julius Caeser on Wikipedia.