When Šuppiluliuma I (13th century BCE) conquered Mitanni, he created two provinces (Aleppo and Carchemish), and distributed the large part of territories of this kingdom between his allies.
C. W. Ceram, The Secret of the Hittites: The Discovery of an Ancient Empire.
In its prime Harran was a major Assyrian city which controlled the point where the road from Damascus joins the highway between Nineveh and Carchemish.
The city, which was destroyed, has not been rediscovered; but it is thought to have been located near the Euphrates and Europos or Carchemish (Djerabis).
He conquered the whole country from Taidu to Irridu, from Mount Kashiar to Eluhat, and from the fortresses of Sudu and Harranu to Carchemish on the Euphrates.