Iran is the native name for Persia. In 1935 the shah (king), Riza Khan Pahlavi, insisted the country be called “Iran” by other nations. (

At the outbreak of World War II, Iran announced its neutrality, but the shah was believed to be pro-German. The Allies feared Germany might seize Iran's oil resources, and at the same time a supply route to the Soviet Union was badly needed. In 1941 Great Britain and the Soviet Union attacked Iran, quickly overcoming resistance. The shah abdicated in favor of Crown Prince Mohammed Riza Pahlavi. United States troops entered Iran in 1942. The Allies made the Trans-Iranian Railway a major supply route to the Soviet Union. During 1943, Iran declared war on Germany, and Allied leaders Churchill, Roosevelt, and Stalin met at Tehran.

At the end of the war, Iran became one of the first areas of cold war conflict, when the Soviet Union, which had set up a secessionist regime in the province of Azerbaijan, refused to withdraw troops it had stationed there. Pressure from the United Nations finally resulted in the troops being removed in 1946. Iranian forces then moved into Azerbaijan, putting an end to the secessionist attempt.

In 1951 Prime Minister Mohammed Mossadegh nationalized the oil industry. In 1953 he forced the shah into exile but was overthrown by the shah's supporters within a week. The shah, who previously had been little more than a figurehead, then began to exercise his full authority.

During the 1960's, the shah instituted wide-ranging economic, political, and social reforms. Huge estates were broken up and the land distributed to the peasants. New programs helped develop industry, improve health conditions, and increase educational opportunities. Women were given equal rights with men. Opposition to the reforms led the shah to suspend parliamentary government, 1961-63, and to suppress all opposition.

In 1967, with prosperity increasing and political stability restored, the shah allowed himself to be formally crowned, 26 years after he came to the throne. The 2,500th anniversary of the founding of the Persian Empire was celebrated in 1971, 10 years after the actual anniversary date.

During the 1970's, large increases in oil prices made it possible for the shah to accelerate the modernization of Iran and to build up the country's military strength on a massive scale. In 1978 protests over the shah's rule began to grow. Much of the opposition came from conservative religious leaders, led by the Ayatollah Ruhollah Khomeini, who opposed modernization because it was contrary to traditional Islamic ways. Many opponents, however, some of them socialists and Communists, demanded a more equal distribution of wealth and an end to dictatorial rule.

In 1979 the shah lost the support of the army and his regime collapsed. He went into exile and the Ayatollah Khomeini became ruler. When the shah visited the United States for medical treatment in October, 1979, militants seized the American embassy in Tehran and its personnel, demanding the United States turn over the shah in exchange for the release of the hostages. The United States refused and a diplomatic crisis ensued. The shah died (of natural causes) in July, 1980, but the hostages were not released until January, 1981.

In September, 1980, Iraq invaded Iran in an attempt to regain border territory it had ceded in 1975. After Iran drove Iraqi forces out of most of the invaded territory in 1982, the war turned into a stalemate. The two nations agreed to a cease-fire in 1988 and a tentative peace settlement in 1990.

Meanwhile, Khomeini died in 1989, leaving the country in the hands of other conservative religious leaders. Little changed politically until 1997, when a religious moderate was elected president by a large majority. I

In December, 2003, a major earthquake struck the city of Bam in southeastern Iran. More than 40,000 people were killed. In 2004, conservatives regained control of the Majlis in parliamentary elections after the Council of Guardians had disqualified many reformist candidates. In 2005, voters elected Mahmoud Ahmadinejad, the mayor of Tehran and a political conservative, as president. In 2005, as in 2004, the Council of Guardians had disqualified large numbers of reformist candidates before the election. In the early 21st century, tensions rose between Iran and other countries, especially the United States. The U.S. government accused Iran of supporting terrorism and seeking to develop nuclear weapons. Iran denied the accusations. In 2003, United Nations (UN) atomic energy inspectors began visiting Iran to try to learn the nature of the country's nuclear program. They criticized Iran for concealing some nuclear activities. In 2004, under international pressure, Iran agreed to suspend its enrichment of uranium, one of the steps involved in preparing uranium for use as a nuclear fuel. Also in 2005, during talks with France, Germany, and the United Kingdom, Iran announced that it would resume nuclear fuel work. In December, 2006, the Security Council passed a resolution banning Iran from trading nuclear-related materials and the following year imposed additional sanctions on Iran because of its continued enrichment of uranium.