Since we studied the play, Julius Caesar in high school, I've always been aware of the term "beware the Ides of March". The Ides of March is the name for the date March 15th on the Roman calendar. The term ides was used for the 15th day of the months of March, May, July, and October, and the 13th day of the other eight months. In Roman times, the Ides of March was a festive day dedicated to the god Mars and a military parade was usually held. In modern times, the term Ides of March is best known as the date that Julius Caesar was assassinated, in 44 BC.
I still remember the passage I had to memorize from the play:
Cowards die many times before their deaths
The valiant never taste of death but once
Of all the wonders I yet have heard
It seems to me most strange that men should fear
Seeing that death, a necessary end,
Will come when it will come