Cloistered Emperor
In 1192, after the birth of Yoritomo's and Masako's second son, Minamoto no Sanetomo, Minamoto no Yoritomo was granted the title of "shōgun" by Cloistered Emperor Go-Shirakawa, who died later that year. Hōjō Tokimasa, as the head of the Hōjō clan, was thus the head of one of the most powerful families in Japan – he was the father-in-law of the "shōgun".