Okay kiddo, so a long time ago there was this place called the Kingdom of Croatia-Slavonia. It was a big area of land that belonged to a king, just like your toys belong to you.
The people who lived there were called Croats and Slavonians. They had their own language and culture, just like you might have a special way of speaking or doing things with your family.
The king who ruled over the Kingdom of Croatia-Slavonia was very important and powerful. He made decisions for the whole area, like a person in charge of a game might make rules for everyone to follow.
People in the Kingdom of Croatia-Slavonia were proud of their culture and heritage, just like you might be proud of your favorite toys or hobbies. They had their own flag and symbols to show off their identity.
Eventually, the Kingdom of Croatia-Slavonia became a part of a bigger country called Austria-Hungary. Just like how sometimes you might share your toys with a friend, the Croats and Slavonians had to share their land and government with other people.
But they still remembered their history and culture, just like you might remember a special toy or memory from your past. The Kingdom of Croatia-Slavonia is now a part of modern-day Croatia, and the people there still celebrate their heritage and traditions.