the years 1185 to 1333 are known as the . this grouping of years is named after city of kamakura which was the center of power of the kamakura shogunate. minamoto no yoritomo was the founder and first shogun of the kamakura shogunate. the period is named after the government of kamakura shogunate. in this period, mongols tried to invade japan between the years 1272 and 1281. japanese were successful at driving away the mongols. but, this badly affected japan. shogunate also became weak and its rule ended in 1333. for a short time, go daigo became the emperor of japan.