Ashura is considered sacred among Sunnis as well, who make up the majority of Muslims worldwide. It is customary to fast from sunrise to sunset on that day, although it is not obligatory. In some countries, it is even observed as a public holiday. According to Islamic tradition, the Prophet Muhammad established it as the first fast day before the month of Ramadan was designated for fasting, giving the day religious significance for most Muslims.
Among Shiites, however, the day has a completely different meaning and has shaped the sect's identity for centuries. It all began on Ashura in the year 680 CE, when Husayn ibn Ali was journeying toward the camp of his supporters near the city of Karbala, in present-day Iraq. Husayn was the son of Ali ibn Abi Talib, the fourth caliph, and the grandson of the Prophet Muhammad. On that basis, he laid claim to the caliphate.

Husayn's supporters believed that leadership of the emerging Muslim empire should remain with Ali's descendants, not with the Umayyad dynasty, a different branch of the Quraysh tribe. However, the newly appointed Umayyad caliph, Yazid ibn Muawiyah, seized the opportunity to assert his control. On October 10, 680, his army attacked Husayn's convoy and massacred dozens of his followers. Since then, Ashura has been observed as a day of mourning for Husayn's death for over 1,345 years.
After the massacre, Husayn's head was severed and sent to Caliph Yazid in Damascus. His body was buried in Karbala. The event became a symbol of ultimate sacrifice in Shiite Islam and a mythic tale of the few standing against the many. As a result, believers commemorate the day each year through prayers and weeping. The tragedy also marked Shiites as a persecuted minority by the Sunni majority, a reality that persisted for centuries, with few exceptions.
Shiites continued to uphold the legitimate claim of the imams, Ali and his descendants, to leadership. These imams were venerated as saints, and many were persecuted and executed by Sunni Islamic empires.

Today, some Shiites still hold public rituals that involve self-flagellation to the point of bleeding. During the ceremony known as "tatbir," participants strike their heads with sharp objects to draw blood as a sign of mourning for Husayn.
Experts suggest these rituals originated outside the Middle East. One theory posits that the custom came from Central Asia to Iran and then spread to the broader Middle East. Another suggests it derived specifically from Christian Orthodox communities in the Caucasus, who practiced bodily self-torment to mourn the death of Jesus. This has led to controversy among Shiite clerics over the legitimacy of the practice.
Iran's Supreme Leader Ayatollah Ali Khamenei has publicly banned the tatbir ritual, calling it a fabricated tradition that should not be practiced. Nonetheless, he did not issue an outright ban, merely stating he would be "disappointed" if it continued. His predecessor, Ayatollah Ruhollah Khomeini, said the ritual was acceptable as long as it caused no harm, but advised against it in general. To curb the practice, some Shiite clerics have suggested donating blood as an alternative.
Ashura is also a time for sermons and proclamations by Shiite clerics, which sometimes stir controversy. Just days ago, influential Iraqi Shiite leader Muqtada al-Sadr declared that Allah's curse still applies to the descendants of the Umayyad dynasty for killing Husayn, calling it a "divine decree." In response, Iraqi Sunni cleric Mohammed Ayash al-Kubaisi pointed out that members of the Umayyad family were closely related to the Prophet Muhammad's family through intermarriage within the Quraysh tribe.