Stefan Dusan takes the Byzantine throne in the 1340s and a revival of a sort takes place, with Bithynia and Ionia reintegrated into the Orthodox Empire. Decline recommences after about 1500, though, due to the growth in power of Western European states able to access Atlantic gold. The Byzantino-Serbian state eventually breaks apart into civil war in the 1530s, with Constantinople eventually ending up a possession of the Portuguese crown.
Trebizond meanwhile maintains her independence thanks to an alliance with Georgia, and by the sixteenth century this Pontic state dominates NE Anatolia and the Crimea. With a strong identity building as the one true remnant of the Roman Empire, the Trapezuntine state continues to thrive as the centuries progress.
Without access to the Aegean, Turkish power in Anatolia comes to be dominated by the city of Antalya, and the Sultanate based here is able to project power across the Mediterranean, acting as an Islamic equivalent to the Italian merchant states, projecting power inland through its vassals too. When the age of nationalism eventually arrives in the 1820s, it is naturally Antalya that becomes the great unifier of the Turkish peoples, although Cappadocia continues to exist with a degree of independence, eventually emerging as a secular nation state.
The Knights of St. John on Rhodes manage to carve out a small chunk of the coast of SE Anatolia, as well as various Aegean Isles and, after the Mediterranean War of the 1740s between Portugal, Venice, Egypt and Sicily, they manage to grab Crete too. The Knights are eventually overthrown in a revolution in 1813, which sees the establishment of a secular federal republic governed from Rhodes, before the capital is transferred to a setpiece rebuilt city of Halicarnassus in 1838.
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