Ivan killed his oldest son

Ivan Ivanovich's relationship with his father began to deteriorate during the later stages of the Livonian War. Angry with his father for his military failures, Ivan demanded to be given command of some troops to liberate besieged Pskov. Their relationship further deteriorated when on 15 November 1581, the Tsar, after seeing his pregnant daughter-in-law wearing unconventionally light clothing, physically assaulted her. In a fit of anger, Ivan murdered his eldest son and heir, Ivan Ivanovich, and the latter's unborn child, which left his younger son, the politically ineffectual Feodor Ivanovich, to inherit the throne, a man whose rule directly led to the end of the Rurikid dynasty and the beginning of the Time of Troubles.