Okay kiddo, let's learn about the Battle of Aljubarrota! It happened a very long time ago in the year 1385 in Portugal.
So there were two sides, the Portuguese and the Castilians. The Castilians wanted to take over Portugal and make it part of their country. But the Portuguese didn't want that to happen, so they got their army together to fight against the Castilians.
The Portuguese army was led by a man named João, who was also known as John of Aviz. He was really brave and he wanted to protect his country from the Castilians. The Castilian army was led by a man named Juan, who was also known as John I of Castile. He wanted to take over Portugal because he thought it would make his country stronger.
The two armies met on a big field called Aljubarrota. The Portuguese army had a really good plan. They made long lines with soldiers called pikemen in front, then archers in the middle, and knights in the back. The pikemen had long sticks called pikes that they could use to defend themselves from the Castilian cavalry. The archers could shoot arrows at the Castilian soldiers from far away, and the knights were really good at riding horses and fighting in close combat.
The Castilians charged at the Portuguese army, but the pikemen stopped them with their long sticks. The archers then shot arrows and killed many of the Castilians. When the Castilian cavalry tried to charge at the Portuguese knights, they were met with a wall of pikes and couldn't get through.
The battle lasted for hours, but eventually the Portuguese won! They protected their country from the Castilians and showed that they were strong and brave. This was a really important battle because it helped make Portugal its own independent country and not be ruled by another country.
So, that's the Battle of Aljubarrota. It was a big fight where the Portuguese protected their country from the Castilians and won!