J.S. Trimingham has famously described Ethiopia as a "beleaguered fortress in the midst of a sea of Islam," implying Christians in Ethiopia have consistently been besieged by Muslims, not vice versa. This thesis challenges this common conception by demonstrating that throughout Ethiopia's medieval period (1270-1555), the time of greatest conflict between the Ethiopian Empire and its Muslim neighbors, Muslim forces did not besiege the Ethiopian Empire. On the contrary, the Ethiopians militarily subjugated their neighboring Muslim sultanates, most prominently Ifat and Adal, and politically divided the sultanates' ruling families to keep them weak. These tactics, designed to wrest control of trade from the sultanates, were resoundingly successful until Muslims unified around military/religious leaders, primary among them being Imam Gran, who in 1531 conquered the Ethiopian Empire. Though Imperial forces reversed the conquest by 1543, a historical focus on this event still feeds the misperception that Ethiopia's history is that of a Christian kingdom ensconced in a fortress to protect itself from a beleaguering "Muslim menace." This thesis concludes to the contrary that the Ethiopian Empire waded aggressively and purposefully into the sea of Islam to beleaguer its many Muslim neighbors.