The 15th is the Ides of March, and you know what that means. You don’t? Oh. It wasn’t good for Julius Caesar — he got stabbed 23 times by his trusted friends on this day in 44 B.C. Fast forward a few thousand years and Ryan Gosling gets fired from George Clooney’s presidential campaign in the political drama The Ides of March. Even Homer Simpson is warned of his downfall on the Ides of March after being the Chosen One of the Stonecutters club. The Ides of March have a doom-filled reputation, but every month has its Ides. Let TIME be your soothsayer and explain exactly why you should, or shouldn’t, beware.