The first evidence of human presence on the small peninsula of Qatar dates from the beginning of the 6th millennium BCE. At that time the climate in eastern Arabia was much wetter than it is nowadays. There were inland wells in abundance and hunters and gatherers could harvest wild cereals. From the beginning of the 4th millennium BCE, however, the climate in the Gulf turned markedly drier. This climatic change triggered early urbanization in Mesopotamia, Egypt, and the Indus Valley. Traders from these three major civilizations have left very few traces in Qatar however. This is probably because the peninsula did not harbour any permanent settlements suitable for entrepôt trade.
It is possible that Qatar was part of Dilmun, a land mentioned by Mesopotamian civilizations as a trade partner, source of raw material, copper, and an entrepôt on the trade route to the Indus Valley. Although the exact location of Dilmun is unclear, it might be associated with the islands of Bahrain, with Qatar, Oman and the nearby coast of Iran in the Persian Gulf.
There is both literary and archaeological evidence of trade between Ancient Mesopotamia and the Indus Valley. What the commerce consisted of is less sure: timber and precious woods, ivory, lapis lazuli, gold and luxury goods such as glazed stone beads, pearls from the Persian Gulf, shell and bone inlays, were among the goods sent to Mesopotamia in exchange for silver, tin, woollen textiles, olive oil and grains. The importance of this trade is shown by the fact that the weights and measures used at Dilmun were in fact identical to those used by the Indus, and were not those used in Southern Mesopotamia.
During the 2nd millennium BCE trade in the Gulf declined as Mesopotamian peoples redirected their attention to the north and west. In the same period Semitic tribes of Eastern Arabia turned to nomadic pastoralism, using domesticated camels for transport. New overland trade routes further diminished the economic importance of the Gulf. Evidence of human activity in Qatar in ancient times is scarce.