Remember that Caesar died in the ides of March (the 15th); what is significant about the day of Cassius's death?
The day of Cassius's death was rather ironic. It was also the day of his birth. (birthday)
Another interesting fact about Cassius's death is that he committed suicide over something that did not happen. Cassius thought that Titinius was surrounded and taken over by enemy. However, it was actually Brutus's men surrounding Titinius telling him of their victory Over Octavius's men.