How did Emperor Amda Tseyon expand Ethiopian power into the Awash valley?

Emperor Amda Tseyon expanded Ethiopian power into the Awash valley through a combination of vigorous military campaigning and strategic administrative consolidation. As a ruler of the Solomonic dynasty, he waged wars against the Muslim state of Ifat, which held hegemony over the region, in response to resistance against his heavy taxation of exports such as gold, ivory, and enslaved people.12

To secure his control over these newly conquered territories, Amda Tseyon established a network of strategic garrisons. He implemented a system of gults, or fiefs, which required the inhabitants of the region to pay tribute to the gult holders. Following initial military successes, Amda Tseyon and his successors utilized brutal pacification campaigns to solidify their authority, eventually extending Solomonic power throughout the Awash valley and as far as Seylac on the Gulf of Aden.12