What are the Ides of March, and why should you beware?

Old painting of Julius Caesar falling, many men surround him, some have knives. Words March 15 at top and Beware the Ides of March at bottom.

What are the Ides of March? Beware the Ides of March! But why? In the ancient Roman calendar, the Ides of March were equivalent to our March 15. The Romans considered the ...