Okay kiddo, so back in the old days, there was an empire called the Byzantine Empire. They were really good at building big walls to keep bad guys out, and they had fancy churches with lots of gold and beautiful mosaics.
But one day, a group of soldiers from another empire called the Ottoman Empire came and attacked the Byzantines. They were really tough and they broke through the walls and took over the capital city, Constantinople.
That was very sad for the Byzantines, but some of them didn't give up. They went out and settled in other parts of the world, like Italy and Greece. They kept their culture and their religion, which was Eastern Orthodox Christianity, and they kept calling themselves Byzantines even though they didn't have an empire anymore.
So even though the Byzantine Empire was gone, the Byzantine people still existed and they had a big impact on the cultures of the places they settled in. And that's what happened after Byzantium, my little friend!