Complex sentence: After repelling Ottoman attacks for over 70 years, Belgrade finally fell in 1521, along with the greater part of the Kingdom of Hungary, and the Serbian Despotate finally fell in 1540, thus marking the Turkish occupation of all Serbian territories.
Split into simpler sentences: After repelling Ottoman attacks for over 70 years, Belgrade finally fell in 1521, along with the greater part of the Kingdom of Hungary. The Serbian Despotate fell in 1540, thus marking the Turkish occupation of all Serbian territories.