Ethiopia's Christians will be confronted from the mid-fifteenth through the mid-seventeenth century by the aggressiveness of the Muslim states, the far-reaching migrations of the Oromo, and the efforts of the Portuguese—who have been summoned to aid in the fight against the forces of Islam—to convert them from Monophysite Christianity to Roman Catholicism.
The effects of the Muslim and Oromo activities and of the civil strife engendered by the Portuguese will leave the empire much weakened by the mid-seventeenth century.
One result is the emergence of regional lords essentially independent of the throne, although in principle subject to it.
Beginning in the thirteenth century, one of the chief problems confronting the Christian kingdom, ruled at this time by the Amhara, is the threat of Muslim encirclement.
By this time, a variety of peoples east and south of the highlands have embraced Islam, and some have established powerful sultanates (or shaykhdoms).
One of these is the sultanate of Ifat in the northeastern Shewan foothills, and another is centered in the Islamic city of Harar farther east.
In the lowlands along the Red Sea are two other important Muslim peoples—the Afar and the Somali.
As mentioned previously, Ifat posed a major threat to the Christian kingdom, but it is finally defeated by Amda Siyon in the mid-fourteenth century after a protracted struggle.
During this conflict, Ifat is supported by other sultanates and by Muslim pastoralists, but for the most part, the Islamicized peoples inhabit small, independent states and are divided by differences in language and culture.
Many of them speak Cushitic languages, unlike the Semitic speakers of Harar.
Some are sedentary cultivators and traders, while others are pastoralists.
As a consequence, unity beyond a single campaign or even the coordination of military activities is difficult to sustain.
Their tendency toward disunity notwithstanding, the Muslim forces continue to pose intermittent threats to the Christian kingdom.
By the late fourteenth century, descendants of the ruling family of Ifat have moved east to the area around Harar and have reinvigorated the old Muslim sultanate of Adal, which becomes the most powerful Muslim entity in the Horn of Africa.
