I thought id step in an correct some of the anachronisms here.
first of all the conflicts between 1200's and 1400's were not between Ethiopians and Somalis.
It was between the amharic speaking solomonic christian abbysinian kingdom centered in gondar the northern highlands and the various multi ethnic and multilingual states in the lowlands the majority of whom were muslim.
The main ones being The Sidamo, the state of Hadiye, the Manz, the fatawajir
and the largest and most influential state Ifat and its successor state Adal that was the center of Islam and was the leader of this coalition.
You should know that not all these states were muslim, some were evenly divided between Islam and the traditional religions mostly versions of Waaq Monotheism.
What united them was resistance to Amhara christian expansion.
The wars started when the Sultante Shoa in the 1220's fell to the Amhara Christians, this was a mulsim dominated state but with at least half the population practicing the Waaq religion.
The vast majority have been conquered and assimilited by the Oromo expansion of the 1550's.
The Oromo were like the Borg, they would not kill millions like the mongols but they would destroy cultures and fully assimilate them so that in another generation they are fully oromo and participate themselves as equals in further conquests.
Something like 1/2 to 3/4 of the Oromo nation is decendent of these groups
that were assimilated, mostly Hadiya and sidamo, but also somalis and afar as well.
I am still surprised when i come across oromos that have pagan great grandfathers with Muslim or christian names.
Somalis were not involved in these wars as a people but were anamolous to the turks in that they were recruited as mercenaries by allot of these states
and they made up most of the manpower of the Sultanate of Adal(harar) along with the Afar.
another point i want to make across was the idea of a large pool of muslims from the middle east available through jihad.
This was not so, although there were a tiny number involved, this was a period were muslim manpower was invested heavily elsewhere, e,g crusades, mongol invasions.
Jihad was not the only attraction for them, they were attracted to spoils of war, and the Amhara Christian state was very poor in gold and resources although having a large population that was highly millitarized.
Allot of these jihadis/mercenaries were attracted to Spain at least untill Las nevas de tolosa were they made up a large part of the muslim force.
There was muslim immigration to the region, but these were mostly desperate refugees escaping the destruction brought by the mongols, my own ancestors are among them.
The first time a purely Amhara christian force came face to face with a purely somali force was when Emperor Amde seyon invaded deep into Somali territory as far as berbera in a series of massive raids in the 1340's.
So you see the political situation is quite different from what many believe, it is a complex set of alliances of states and ethnicities.
It was not just Muslim Ethiopia against Muslims.
Till the 1890's Abbysinia or as Haile Selasie renamed it Ethiopia was the northern highlands from shoa to tigray.
The area that is Eritrea today was not part of it and was hostile to it.
Since the collpase of axsum the area that is today Eritrea was sepearate from the rest of ethiopia, and from the middle ages was ruled by the Medri Bahri the Sea king that ruled over a loose confederation of states that were muslim and christian and hostile to Ethiopia.
I SAID NO MORE ETHIOPIA ANYONE WHO MENTIONS THAT COUNTRY AGAIN ON THIS THREAD WILL BE EATEN BY A HOARD OF EVIL KITTENS! A MORE POWERFUL ETHIOPIA IS NOT HAPPENING! MOVE ON! WHY CANT YOU LEAVE IT!