Ashura 101

From PBS:

Ashura-2008-2 December 18 marked the beginning of the month of Moharram. Shiites, and in particular Iranians, have been mourning the killing of their third Imam, Hossein, the quintessential martyr, since his death in the battle of Karbala on October 10, 680, which falls on Ashura, the 10th day of Moharram. Ashura has been commemorated for at least a thousand years, beginning probably in Baghdad, Iraq, in the 4th Islamic century. Tradition holds that Imam Hossein and 72 of his followers were slain on that day after fighting bravely with the much larger army of the Umayyad Caliph, Yazid ibn Moaaviyeh, which some historians have said was 100,000 men strong.

The death of Imam Hossein, his friends, followers and members of his family by a Sunni Caliph is perhaps the main reason that Shiism is considered a rebellious sect in Islam. Because the Shiites have been a minority throughout the history of Islam, they have transformed the historical battle of Karbala to symbolize ideological confrontation with the ruling elite, and have used a powerful combination of actual events and legend to stir up great emotion; it has been an occasion to complain bitterly about their marginalization in much of the Islamic world and to demand their rights. They invoke Imam Hossein's famous quote that, “Every day is Ashura, and every land is Karbala.”

More here.