But then later, Hassan, he goes into something of retirement. He dies in his mid-40s. And some accounts say that he was assassinated, poisoned by his wife, maybe due to the Umayyads, who didn't want him around. And then in 680, Mawawiya dies. Now, according to the treaty between Mawawiya and Hassan, it should have been some form of an election there. But Mawawiya says, or before his death, he makes Yazid the successor. And so Hussein, who is another son of Ali, Hassan's younger brother, and by this point, Hassan is dead, he says, hey, this is a breach of the treaty, and does not pledge his allegiance to Yazid.