Ezana was the 4th century king of Axum in whose region Christianity was introduced to Ethiopia. He conquered the Nile valley realm of Kush, and extended the frontiers of his kingdom to include, not only what is now Ethiopia, but also parts of Sudan and Somalia. According to the inscriptions on the stone, the kingdom extended to both sides of the Red Sea, and also included territory of both Asia and Africa. His capital was the city of Axum. As ruler, he extended Axum's boundaries, and he decorated his capital with buildings and monuments including obelisks. He introduced the title of "King of Kings" used by the Ethiopian monarchy into the 1970s.