They were later isolated from the rest of Ethiopia by the Oromo people , who settled around the lake .
Tradition states that when the Muslim Ahmad ibn Ibrahim al - Ghazi conquered Ethiopia , the Christians of the area took refuge on its islands .
Christians were later isolated from the rest of Ethiopia by the Oromo people , who settled around the lake .
Tradition states that when the Muslim Ahmad ibn Ibrahim al - Ghazi conquered Ethiopia , the Christians of the area took refuge on its islands .