And this is known in the Shia tradition as the tragedy of Karbala. Because at Karbala, you have Hussein's family gets massacred. There's an account that his six-month-old son is beheaded and killed along with Hussein. And so this becomes the defining event of the Shia tradition, the tragedy of Karbala. We've already talked their belief that Ali should have been the caliph from the beginning. But now you have Yazid, purported caliph, who murders, who kills off, according to Shia tradition, a significant member of Muhammad's family and does this in bloody, bloody fashion. And so even to this day, a significant part of the Shia tradition is mourning what happens at the Battle of Karbala.