re-upping something I noticed when ISIS first arose. The below two maps compare (L) modern Shia-Sunni-Kurd territory; (2) Late Bronze (~1250 BC) Babyonia-Assyria. Border between Shia-Sunni and Babylonia-Assyria has changed only slightly in 3000+years. 
2/ maximum extent of ISIS caliphate was very similar to extent of Assyrian Empire in some Bronze Age phases. Modern Mosul, most important ISIS city, is located at ancient Assyrian capital.
3/ ISIS routes as they advanced on Baghdad in 2014 were more or less identical to the routes follower by, for example, Tukulti-Ninurta 2: from Raqqa down the Euphrates, from Mosul down the Tigris.
4/ the Elamites (in modern-day Iran) were important neighbors to both Babylonia and Assyria in Bronze Age.
