South Arabia
Yemen and the incense country: highland kingdoms that grew rich carrying frankincense north, and the confessional states that later held the same mountains. Ground where a caravan route, a monsoon port and a terrace wall each supported a polity, and where the imperial armies that came for them — Aksumite, Ayyubid, Ottoman — could take the coast and not the highlands.
The line below is a time axis. Position on it is date, so concurrency is visible: concurrent polities sit side by side rather than in sequence.
8 sourced edges run between this region and another, to Ethiopian Empire, Hujrid Dynasty, Kingdom of Aksum, Ayyubid Sultanate, Fatimid Caliphate, Abbasid Caliphate and Mamluk Sultanate. Those are not drawn on this line — a thread that crossed regions would assert a sequence nobody cited — but they are on each polity’s own page.