Every year, in the month of Muharram, millions of Shi'as and Sunnis alike, mourn Imam Hussain's martyrdom. It is regrettable, however, that of these mourners very few focus their attention on the objective for which the Imam not only sacrificed his life but also the lives of his kith and kin.
In AD 638, six years after the death of the Prophet Muhammad, Islam's second caliph Umar recognized the necessity of a calendar known as Hijri calender, to govern the affairs of the Muslims. This was a practical matter.