I'm surprised noone yet has brought Mesopotamia/Iraq up. It's been represented by ancient empires only, and different too - Sumerian, Babylonian, in earlier iterations Assyrians, too - and lacks medieval and modern leaders. Ironically, two actua leaders from that region head two different civs: Saladin and Harun al-Rashid who represent the Arabs. The Arabs, instead have had their capitals in Mecca and Cairo. So Egypt actually has a medieval representation, just as the central region in the time of Saladin. Mesopotamia, similarly to Egypt, has been mostly ruled by foreigners: Persians, Macedonians, Arabs, Turkish, until the 20.c. You could argue that after a while the Abbasids can no longer be viewed as foreigners. But think about having an Abbasid caliph as a medieval leader for the, say, Babylonians. Nasir li-Din Allah leads the Babylonians in 1225!