Husayn’s historical importance was limited before his martyrdom at Karbala in 680, having only a minuscule chance of ever exercising any power. Husayn had a claim on the Caliph position, several traditions acknowledging that he had been promised it upon the death of Caliph Mu’awiyya.
But when Mu’awiyya actually died in 680 and his son Yazid 1 was appointed Caliph, Husayn decided to listen to all those voices that had invoked him to act against the Umayyad rulers of Syria.
Husayn was at the time stationed in Madina, together with a small group of his followers. He received many supportive letters from inhabitants of Kufa in Iraq, so he sent his cousin Muslim Ibn Aqil to Kufa. He wrote back confirming that there were thousands of supporters for Husayn. Soon thereafter, however, Muslims was captured and executed by the governor of Iraq, ‘Ubaid Allah.
‘Ubaid Allah established scouts all along the road from Madina to Kufa. Unaware that his situation was strongly deteriorating, Husayn embarked on the journey to Kufa, with a following of 70 men, women, and children.
Even when he clearly saw that Umayyad troops were following his every move, he continued, and after 10 days, he and his party were halted by ‘Ubaid Allah’s 4,000 troops at Karbala, less than 50 km from Kufa.
What subsequently happened at this spot is of central importance to most Shi’is. Surrounded, Husayn’s party could not proceed. What followed, appears neither to have been ordered nor intended by Caliph Yazid.
Husayn and his party, deprived of water, resolutely moved forward. A battle ensued, but due to the differences in strength, it quickly turned into a massacre. Husayn was wounded in several places and died slowly with his son in his hands.
Even if the majority of traditions appear to present Yazid as treating the rest of the group with much respect, providing for their needs, and bringing them safely back to Madina, Shi’i texts nevertheless present Yazid as a brutal and degenerate ruler.
The happenings at Karbala, as well as the 10 days leading up to it, are remembered in the celebrations of the month of Muharram, concluded by Ashura. The religious texts connected to the martyrdom of Husayn, are believed to be strongly influenced by Christian texts and bears much resemblance to the passion of Christ.
Husayn is given a key to Paradise, and this is to be used on the day of judgment, but only by those that have mourned over Husayn’s death during the ceremonies of Muharram.