From 1941 to 1979, Iran was ruled by King Mohammad Reza Pahlavi, the Shah.

On February 11, 1979, the Islamic Revolution swept the country.

The government was replaced with an Islamic republic, which continues to this day.

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In the decades before the Islamic revolution of 1979, Iran was ruled by the Shah, whose dictatorship repressed dissent and restricted political freedoms.

But he also he pushed the country to adopt Western-oriented secular modernization, allowing some degree of cultural freedom.

Under the Shah's rule, Iran's economy and educational opportunities expanded. Britain and the US counted Iran as their major ally in the Middle East, and the Shah forcefully industrialized large segments of the country.

But the Shah's increasingly authoritarian measures and his eventual dismissal of multiparty rule set the stage for the infamous revolution.

Still, for a period of almost 40 years, the Shah led Iran through a series of sweeping changes.