Antipope

Okay kiddo, so you know how when you play pretend with your friends sometimes there's more than one king or queen or leader? And sometimes they don't agree on who should be in charge?

Well, that's kind of like what happened a long, long time ago in the Catholic Church. There was a disagreement over who should be the Pope, which is like the top leader of the Church. Some people thought one person should be Pope, but others disagreed and chose a different person to be Pope.

The person who wasn't chosen by everyone to be the real Pope is called an "antipope." It's like they're pretending to be the Pope, but not everyone agrees that they really are.

So, basically, an antipope is someone who claims to be the Pope, but not everyone believes that they are the real leader of the Catholic Church.