There was increasing syncretism between the Sumerian and Akkadian cultures and deities, with the Akkadians typically preferring to worship fewer deities but elevating them to greater positions of power. Circa 2335 BC, Sargon of Akkad conquered all of Mesopotamia, uniting its inhabitants into the world's first empire and spreading its domination into ancient Iran, the Levant, Anatolia, Canaan and the Arabian Peninsula. The Akkadian Empire endured for two centuries before collapsing due to economic decline, internal strife and attacks from the north east by the Gutian people.