The Kush
This Kingdom was mentioned throughout Egypt as having an abundance of gold and other valuable natural resources, as well as a deep history and sophisticated urban society. Due to that, they were conquered by Egypt and exploited from 1500-1000 B.C.
By the 9th century, Egyptian instability allowed the Kushites to gain their independence, and they then turned around in 750, and conquered Egypt. It was they, who revived the practice of building pyramids and implemented construction projects across the Sudan.
Both the Kush and Egyptian Kingdoms were then ousted by an Assyrian invasion, so the Kush moved to a different area, and developed their own form of writing that we’ve yet to translate, then they faded away. The decline of the Kingdom of Kush, is still one of greatest mysteries of the ancient world.