This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Iraq's September 1980 invasion of Iran, driven by Saddam Hussein's territorial claim over the Shatt al-Arab waterway and his calculation that Iran's post-revolutionary government was militarily weak, opened eight years of trench warfare between the two countries. The Republic of Iraq under Hussein and the Ba'ath Party was backed for much of the war by the Gulf Arab states, the Soviet Union and, increasingly after 1982, the United States and Western Europe. Iran, under Ayatollah Ruhollah Khomeini's post-revolutionary government, carried its war effort disproportionately through Revolutionary Guard volunteer forces recruited in large numbers from a population still animated by the recent revolution.
The conflict included chemical weapons use against Iranian troops and Iraqi Kurdish civilians, and missile exchanges between the two countries' cities known as the War of the Cities. It ended in a stalemate substantially along the prewar border under a United Nations Security Council Resolution 598 ceasefire that took effect in August 1988, with neither side gaining significant territory despite roughly eight years of fighting and enormous casualties on both sides.