The Kanem-Bornu Empire counter-attacked a century later under Ali Gaji. Kanem was retaken by Ali's son after a great battle at Garni Kiyala, forcing the Bulala to move east, where they were to remain a menace for centuries to Kanem-Bornu. It continued also to be a flourishing kingdom: the traveller Leo Africanus even thought that the Bulala's reign was richer than Kanem-Bornu for its prosperous trade with Egypt.