Byzantism is a term used to describe the Byzantine Empire, which was a big empire that existed many, many years ago. Think of it like a really big kingdom ruled by kings and queens, but instead of being in one place, it spanned across different parts of Europe and Asia. The people who lived in this empire were called Byzantines.
The Byzantines were very rich and powerful, and they had a lot of fancy buildings and art. They loved to show off their wealth and power, and they did this through their art and architecture. They built really big cathedrals and palaces with lots of gold and bright colors, and they made beautiful mosaics and paintings.
The Byzantines also had a strong religion called Eastern Orthodox Christianity, which was a little different from the Christianity that we know today. They had their own special way of praying and worshiping, and their religious leaders were called patriarchs.
The Byzantine empire was very important in Ancient history because it united many different cultures and civilizations. The Byzantines also had a big impact on language, art, and religion, and their contributions are still felt today. However, like all kingdoms, the Byzantine Empire eventually fell and was replaced by other empires in the following centuries.