Okay kiddo, so imagine there were two really big groups of people a long time ago. They were called the Romans and the Gauls. They didn't like each other very much and they would fight often.
One day, in a place called Ancyra, there was a big battle between the Romans and the Gauls. It was a very intense fight with lots of shouting, swords clashing and arrows flying through the air.
The Gauls thought they were going to win, but the Romans had a sneaky trick up their sleeves. They pretended like they were losing and started running away to trick the Gauls into following them. But then, the Romans suddenly turned around and attacked the Gauls from behind while they were chasing them.
This really surprised the Gauls and they were caught off guard. They tried to fight back, but it was too late. The Romans were too strong and they ended up winning the battle.
So, that's what happened in the Battle of Ancyra. The Romans used a trick to beat the Gauls and it worked really well.