Amda Seyon (also Amde Tsiyon and other variants, Ge'ez ዐምደ ፡ ጽዮን ʿamda ṣiyōn, Amharic āmde ṣiyōn, "Pillar of Zion") was Emperor of Ethiopia (1314–1344; throne name Gebre Mesqel Ge'ez ገብረ ፡ መስቀል gabra masḳal, Amh. gebre mesḳel, "slave of the cross"), and a member of the Solomonic dynasty. According to the British expert on Ethiopia, Edward Ullendorff, "Amde Tseyon was one of the most outstanding Ethiopian kings of any age and a singular figure dominating the Horn of Africa in the fourteenth century." His conquests of Muslim borderlands greatly expanded Ethiopian territory and power in the region, maintained for centuries after his death. Amda Seyon asserted the strength of the newly (1270) installed Solomonic dynasty and therefore legitimized it. These expansions further provided for the spread of Christianity to frontier areas, sparking a long era of proselytization, Christianization, and integration of previously peripheral areas.