Iraq is the name of the state that currently partially encompasses the territory of the civilization of ancient Mesopotamia. This civilization came into being between the Tigris and Euphrates rivers. These rivers flow into the Persian Gulf, through the State of Iraq. The Hashemite Kingdom of Iraq, also known as Mandatory Iraq in its early phase, was established by the Anglo-Iraqi treaty of 1922 resulting from the 1920 Iraqi revolt against British rule. It is centered in Lower Mesopotamia (corresponding to historical Babylonia, later also known as ?Ir?q-i ?Arab) but also includes part of Upper Mesopotamia and of the Syrian Desert and the Arabian Desert. The history of this area has witnessed some of the world's earliest writing, literature, sciences, mathematics, laws and philosophies; hence its common epithet, the Cradle of Civilization.