information:classification, structural:scholar_edition
Tasu'a and Ashura marches (10–11 December)

As the days of Tasu'a and Ashura (10 and 11 December) approached, to prevent a deadly showdown, the Shah began to draw back. In negotiations with Ayatollah Shariatmadari, the Shah ordered the release of 120 political prisoners and Karim Sanjabi, and on 8 December revoked the ban on street demonstrations. Permits were issued for the marchers, and troops were removed from the procession's path. In turn, Shariatmadari pledged that to make sure that there would be no violence during the demonstrations.

On 10 and 11 December 1978, the days of Tasu'a and Ashura, between 6 and 9 million anti-Shah demonstrators marched throughout Iran. According to one historian, "even discounting for exaggeration, these figures may represent the largest protest event in history." The marches were led by Ayatollah Taleghani and National Front leader Karim Sanjabi, thus symbolizing the "unity" of the secular and religious opposition. The mullahs and bazaaris effectively policed the gathering, and protesters who attempted to initiate violence were restrained.

More than 10% of the country marched in anti-Shah demonstrations on the two days, possibly a higher percentage than any previous revolution. It is rare for a revolution to involve as much as 1 percent of a country's population; the French, Russian, and Romanian revolutions may have passed the 1 percent mark.