Ivan IV "The Terrible" was the first Tsar of all Russias and was crowned in 1547. He extended Russian territories and opened the route to Siberia in successful campaigns against Tartars. He increased his personal power to the point of generating an autocracy that isolated him progressively from the council of Boyars. He had a complex personality and his acts were impregnated by a profound religiousness, episodes of rage, mood changes and a sense of "personal fate". All these traits configure the controversial "temporal lobe personality". The possible association between these personality traits and the eventual epilepsy that Ivan IV could suffer, is discussed. This association is called "temporal lobe syndrome". Considering the mood changes, with severe irritability and episodes of control loss alternated with feelings of guilt, sadness and isolation, another possibility is that the Tsar had an affective bipolar disorder or, less probably, a personality disorder.