Here's a look at what you need to know about the history of Iraq since the 1920's.
1920s-1930s 1921 - After the defeat of the Ottoman Empire during World War I, Great Britain gains control of the area. It sets up a government in Mesopotamia and renames the country Iraq.
1924 - The new Constitutional Assembly of Iraq meets to consider the Anglo-Iraq treaty. The treaty would compel Iraq to honor all agreements made by Great Britain previously, including oil concessions. In order to compel Iraq to accept the treaty, Great Britain threatens to withdraw and leave Iraq vulnerable to Saudi Arabia or Turkey. The treaty is ratified.
October 3, 1932 - Iraq becomes an independent nation with Baghdad as its capital, and is admitted to the League of Nations.
1940s March 22, 1945 - Iraq becomes a founding member of the Arab League.
December 21, 1945 - Iraq becomes a member of the United Nations.
1950s-1960s July 14, 1958 - King Faisal is killed in a coup led by Abdul Karim Kassem.
October 1959 - A group, including Saddam Hussein, attacks the motorcade of Abdul Karim Kassem. The assassination attempt fails and most of the attackers are killed. Hussein escapes and flees to Syria.
February 1963 - Kassem is overthrown and executed. The Baath Party assumes control of the government. Hussein returns from Cairo, Egypt. The new Baath government is overthrown before the end of the year.
July 17, 1968 - In a coup, Major General Ahmed Hassan al-Bakr of the Baath party becomes Iraq's new president. Saddam Hussein becomes the secretary and acting deputy chairman of the Revolutionary Command Council.
1970s October 1973 - Iraq fights Israel in the Yom Kippur war.
March 6, 1975 - Saddam Hussein and Shah Mohammed Reza Pahlavi of Iran meet to discuss a treaty. The Algiers Accord is signed by both countries later in the year.
October 1978 - At the Shah's insistence, Hussein expels Ayatollah Ruhollah Khomeini from Iraq, where he has been in exile for 13 years.
February 1979 - The Ayatollah returns to Iran to lead the country, after the ouster of the Shah in January.
July 16, 1979 - Hussein takes over as president of Iraq.
1979 - In response to the Ayatollah's call for the overthrow of the Baathist regime, comprised mostly of Sunni Muslims, President Hussein expels 40,000 Shiite Muslims. Hussein also orders the execution of Ayatollah Mohammed al-Bakr Sadr, an ally of Ayatollah Khomeini.
1980s September 22, 1980 - Iraq launches an air attack against Iran, beginning the Iran-Iraq war. In 1984 and 1986 Iraq is accused of using mustard gas and other chemical weapons against Iran. The war ends in a stalemate in 1988.
March 16, 1988 - Iraq uses poison gas against the Kurdish people in Halabja in Northern Iraq. Thousands of people are believed to have died in the attack.
1990s August 2, 1990 - Iraq invades Kuwait.
January 17, 1991 - Operation Desert Storm begins.
February 28, 1991 - A ceasefire in the Gulf War takes effect.
March 1991 - After the coalition expels Iraq from Kuwait, the U.S. encourages the Kurds to rebel. However, Iraq crushes the rebellion and one million Kurds flee to Turkey.
April 3, 1991 - The U.N. passes Security Council Resolution 687. It establishes UNSCOM.
April 6, 1991 - Iraq accepts SCR 687.
April 18, 1991 - Under the terms of SCR 687, Iraq gives a detailed account of its weapons inventory. It states that it has no biological weapons program.