Iran: Islamic Republic

On April 1, 1979, a referendum was held, the outcome of which was that Iran was declared an Islamic Republic.  This act formally deposed the Shah, who had left country in January.  The officially announced vote totals claimed that over 98% of the vote was for the new republic.

Work would continue on a new constitution that would be passed later in the year, but it was on this day Iran officially became an Islamic state.