The Prophet, Fatimah, Ali, Hassan and Hussain are the five key figures, panj tan pak, in Shia theology and history. The Shias maintain that the Islamic history began to go wrong when Ali, married to Fatimah, daughter of the Prophet, was not made the first caliph after the death of his father-in law.
To make matter worse Ali was assassinated. Ali's two sons, Hassan and Hussain, following in their father's footsteps, opposed tyranny and upheld the puritan principles of Islam both were also martyred. Hussain was killed, facing impossible odds on a battlefield with his family and followers at Karbala.
Hussain's challenge of Yazid and his death at Karbala are among the most significant events in Muslim history. About 70 men, including Hussain's infant son, Asghar, were slaughtered by an army of thousands.
The only male member to survive was Zain-ul- Abedin, Hussain's son, who was then ill, and from whom come the Sayyed, the descendants of the Prophet. After the battle was over Hussain's head was cut from his body and brought to Yazid's governor.
Hussain's action established anew the principle of challenging at all costs any authority deviating from the Islamic ideal. The struggle between Hussain and Yazid is the classic confrontation between good and evil. Hussain represented the virtues found in the ideal of Islam while Yazid symbolised despotism, dynasty and temporal power.
The deaths laid the foundations of Shia mythology. Hussain's alam, flag, horse, and tazya, representation of his shrine at Karbala are universal symbols of mourning.
The very names of Hussain's family: Fatimah and Zainab, his mother and sister, and Abbas, Zain-ul-Abedin and Ashgar, his brother and sons have become common in Shia households. In the month of Muharram, Shias mourn for the events of Karbala for ten days.
During this period, Shias mourn, flagellate themselves, bring out processions symbolic of Karbala, and recite moving poems of the tragedy at Karbala which reduce those present to tears and quivering rapture.