 Artifacts, and even colonies of this Uruk civilization have been found over a wide area—from the Taurus Mountains in Turkey, to the Mediterranean Sea in the west, and as far east as central Iran.The Uruk period civilization, exported by Sumerian traders and colonists (like that found at Tell Brak), had an effect on all surrounding peoples, who gradually evolved their own comparable, competing economies and cultures.The cities of Sumer could not maintain remote, long-distance colonies by military force.