Long time ago in Europe, there were three countries called Poland, Lithuania and Ruthenia. They all decided to come together and become one big country called the Polish-Lithuanian-Ruthenian Commonwealth.
Just like how a family has a mom and dad, the Commonwealth had a king and queen. They were in charge of making rules and decisions for the country.
People in the Commonwealth spoke different languages, but they all still worked together and helped each other out. They had a lot of cool traditions and celebrations, like colorful parades and big feasts with yummy food.
The Commonwealth lasted for a long time, but eventually it started to have some problems. Other countries wanted to take over some of their land and they had disagreements about things like religion. Eventually, the Commonwealth stopped being a big country and the three original countries became separate again.