The country that is now Iraq occupies a large part of the region
once known as Mesopotamia, which has hosted numerous cultures
over the centuries. Human civilizations, including the Sumerian,
Babylonian, Assyrian and Parthian cultures flourished in the land
between the Tigris and Euphrates rivers since 3000 B.C. In the
seventh century Islam spread quickly in the region, and in the
eighth century the Abbasid family established a caliphate with
Baghdad as its capital.
Mongols, with Genghis Khan as their leader, conquered Baghdad
in the 13th century and razed the city. Mesopotamia fell to the
Ottoman Empire in the 16th century, and remained under Ottoman
rule until the British invaded in World War I.