Quotes of the Day

Iran's revolution has now run through a full cycle. A gruesomely captivating video of a young woman — laid out on a Tehran street after apparently being shot, blood pouring from her mouth and then across her face — swept Twitter, Facebook and other websites this weekend. The woman rapidly became a symbol of Iran's escalating crisis, from a political confrontation to far more ominous physical clashes. Some sites refer to the woman as Neda, Farsi for "the voice" or "the call." Tributes that incorporate startlingly up-close footage of her dying have started to spring up on YouTube.

Although it is not yet clear who shot Neda (a soldier? a pro-government militant? an accidental misfiring?), her death may have changed everything. The cycles of mourning in Shi'ite Islam actually provide a schedule for political combat — a way to generate or revive momentum. Shi'ite Muslims mourn their dead on the third, seventh and 40th days after a death, and these commemorations are a pivotal part of Iran's rich history. During the revolution, the pattern of confrontations between the Shah's security forces and the revolutionaries often played out in 40-day cycles.

The first clashes in January 1978 produced two deaths that were then commemorated on the 40th day in mass gatherings, which in turn produced new confrontations with security forces — and new deaths. Those deaths then generated another 40-day period of mourning, new clashes and further deaths. The cycle continued throughout most of the year until the Shah's ouster in January 1979.

The same cycle has already become an undercurrent in Iran's current crisis. The largest demonstration, on June 18, was called by opposition leader Mir-Hossein Mousavi to commemorate the deaths of protesters three days after they were killed.

Shi'ite mourning is not simply a time to react with sadness. Particularly in times of conflict, it is also an opportunity for renewal. The commemorations for Neda and the others killed this weekend are still to come. And the 40th-day events are usually the largest and most important.

Neda is already being hailed as a martyr, a second important concept in Shi'ism. With the reported deaths of 19 people on June 20, martyrdom provides a potent force that could further deepen public anger at Iran's regime.

The belief in martyrdom is central to modern politics as well as Shi'ite tradition dating back centuries in Iran. It, too, helped propel the 1979 revolution. It sustained Iran during the eight-year war with Iraq, when more than 120,000 Iranians died in the bloodiest modern Middle East conflict. Most major Iranian cities have a martyrs' museum or a martyrs' cemetery.

The first Shi'ite martyr was Hussein, the Prophet Muhammad's grandson. He believed it was better to die fighting injustice than to live with injustice under what he believed was illegitimate rule.

In the 7th century, Hussein and a band of fewer than 100 people, including women and children, took on the mighty Umayyad dynasty in Karbala, an ancient city in Mesopotamia now in modern-day Iraq. They knew they would be massacred.

Fourteen centuries later, Hussein's tomb in Karbala is one of the two holiest Shi'ite shrines — millions of Iranians make pilgrimages there every year. Just as Christians re-enact Jesus' procession bearing the cross past the 14 stops to Calvary before his crucifixion, so, too, do Shi'ites every year re-enact Hussein's martyrdom in an Islamic passion play during the holy period of Ashura.

Because of Hussein, revolt against tyranny became part of Shi'ite tradition. Indeed, protest and martyrdom are widely considered duties to God. And nowhere is the practice more honored than in Iran, the world's largest Shi'ite country.

The revolutionaries exploited the deep passion of martyrdom as well as the timetable of Shi'ite mourning in whipping up greater opposition to Shah Mohammed Reza Pahlavi. With the deaths of Neda and others, they may now find the same phenomena used against them.

• Robin Wright