The samurai Minamoto no Yoritomo died in 1199. It is said that he fell from a horse and so he died. But some researchers support the theory that Minamoto no Yoritomo was assassinated by someone, and that the assassin was his supporter Hojo clan. Indeed, they cleared Yoritomo's sons Minamoto no Yoriie who was the second shogun and Minamoto no Sanetomo who was the third shogun from the political community. After that, both of them were killed. Thats how his reign came to an end.