kobo is part of a mid-altitude area which lies between the ethiopian highlands to the west and the afar depression to the east. the northern portion of this area is known as raya. raya is a flat plain which extends north from kobo woreda in the amhara region all the way to the raya azebo woreda in the tigray region. similar areas exist on the eastern edges of yejju, wollo, and shewa further south. this area has been involved in disputes between the christian highlanders and muslims from the east since the time of the ifat sultanate (13th century). much of the early conflict took place further south on the eastern border of what is now shewa. however, in the 16th century, the raya area was the site of an important conflict in ethiopian history between the armies of the general of adal, ahmad ibn ibrahim al-ghazi, known better amongst ethiopians as imam ahmed gragn, and the abyssinian forces of lebna dengel. this infamous period of conflict was known as the ethiopian-adal war. the ethiopians asked for help from the portuguese, who arrived at port of massawa on february 10, 1541. in april 1542 the two armies met north of lake ashenge (near korem in tigray). this marked the first use of firearms by the abyssinian military.