After the death of Mu‘āwīyah the son of Abū Sufyān, his son Yazīd came into power as a caliph. This was in direct contradiction with the conditions of the truce that Mu‘āwīyah had signed with Imam Ḥasan (a) two decades earlier, where the caliphate was meant to return to Imam Ḥusayn (a). As Yazīd came into power and the article of the truce was broken, he began demanding allegiance from Imam Ḥusayn in order to get support and legitimacy for his rule.