Charles I was at odds with the English Parliament for most of his reign, which is like trying to get a cat to do tricks for you - it's just not going to happen. He kept dissolving Parliament and ruling on his own, which made everyone very grumpy. It's like he thought he was the king of the world or something (spoiler alert: he wasn't).
Things came to a head (pun intended) when Charles I tried to arrest some members of Parliament, which is like trying to kill a hydra - for every head you cut off, two more will grow back. The English Civil War broke out, and Charles I found himself on the losing side. Whoops.
The war was a real mess, with brother fighting against brother and everyone in between. It was like a big game of Game of Thrones, but with more tights and fewer dragons. In the end, Charles I was defeated and put on trial for high treason.
