Tibet and the Himalaya

The plateau, which is high enough that the empires around it could not campaign on it and cold enough that it fed itself. For a century and a half Tibet took territory from Tang China and the caliphate at the same time, and then turned into something no other polity here became: a country governed by its monasteries.

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.

1 sourced edge runs between this region and another, to Mongol Empire. 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.