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Mu`awiyah, who became the first of the Umayyad dynasty Caliphs. And so, the Caliphate (meaning the political leadership of the Islamic nation) passed out of the hands of the descendants of `Alí.
But there was a small group of people who continued to believe that leadership in Islam belonged by right to the family of `Ali. They continued to follow Hasan as the rightful guide for Muslims. After Hasan’s death in 669 CE, this group gathered around Hasan’s younger brother, Husayn. This group later becomes known as Shi`at `Alí (Arabic, meaning the “party of Alí”) and nowadays just as Shí’a. For the Shí’a, the true successor to the Prophet and the 1st Imám is Imám ‘Alí. All the subsequent Imáms are the male descendants of the union of Imám ’Alí and Fātima. The Imámate is passed on from father to usually the eldest son or surviving son.
To go back to Husayn’s life: Mu`awiyah is now Caliph. Husayn is not active in public life during this time. After Mu`awiyah’s death, his son Yazíd becomes the Caliph, Historians say Husayn was persuaded to leave Medína and set out for Kúfa, but he was intercepted on the way at a place called Karbalā’ (which is about 80 miles south of Baghdad). The year is 680 CE. Husayn was surrounded and killed, together with his seventy-two companions.
The significance of the figure of Husayn and his martyrdom for the Shí’a cannot be over-emphasized. It is definitional for Shí’a ethos and psyche. Husayn’s martyrdom continues to this day to be the most important commemoration in the Shí’a calendar (the day is called Ashura and is the 10th day of the month of Muharram in the Islamic calendar).
The Twelver Shí’a (Ithná-‘Asharíyyih)
After Imám Husayn’s martyrdom, there was some disagreement among the Shí’as over who was to be the next Imám. This issue appears several other times in the future at the passing of each Imám. Each Imám is said to be appointed by the previous one, but sometimes there was disagreement as to which son was the appointed next Imám. It is complicated because in those days, usually the men had several wives and concubines, and therefore many children. The genealogy of the Imáms is shown in the figure below. Also indicated in the figure are some of the branches of the Shí’a. The majority of the Shí’a today belong to the branch known as the Twelver Shí’a’s (Ithná-’Asharíyyih). They believe in the twelve Imáms, the first one being ‘Alí and the last one being the 12th Imám, who is also known by the title Imám Mahdí (means “One who is guided”).