Bahri Negassi Yeshaq fought back the invading Ottoman Turks by leading the local peasantry recapturing Debarwa, the capital of his kingdom of Medri Bahri.
When the Ottoman general Ozdemir Pasha, who had been made governor of the Ottoman province of Habesh, crossed over from Jeddah in 1557 and occupied Massawa, Hirgigo and finally Debarwa, capital of the Bahri Negassi, Yeshaq led the local peasantry against the invaders, recapturing Debarwa and seizing the “immense treasure” the invaders piled up within.
Although he enjoyed good relations with Emperor Galawdewos of Abyssinya, his relations with his successors were not as positive. In 1560, the year after Menas became emperor, Bahri Negassi Yeshaq revolted against the new Emperor. While he was successful at first, eventually Menas drove Yeshaq out of Tigray, and the noble was forced to seek refuge at the court of his former enemy. In return for ceding the town of Debarwa, Ozdemur Pasha extended military support to the exiled Bahri Negassi, and Yeshaq led an army into Tigray and the other northern provinces.