: On the afternoon of June 3, 1963, Khomeini delivered a speech in which he warned the Shah that if he did not change his ways the day would come when the people would offer up thanks for his departure from the country. The immediate effect of the Imam's speech was his arrest two days later at 3 a.m. by a group of commandos, who hastily transferred him to the Qasr Prison in Tehran. As dawn broke on June 4, the news of his arrest spread first through Qom and then to other cities. Masses of angry demonstrators were confronted by tanks and ruthlessly slaughtered. It was not until six days later that order was fully restored. This uprising of Khordad 15, 1342 (the day in the Iranian calendar on which it began) marked a turning point in Iranian history. The events of the 15th of Khordadcan indeed be characterized as the prelude to the Islamic Revolution of 1978-79.
