Although they had predecessors in earlier military and administrative officers, the samurai truly emerged during the Kamakura shogunate, ruling from c.1185 to 1333. They became the ruling political class, with significant power but also significant responsibility. During the 13th century, the samurai proved themselves as adept warriors against the invading Mongols. During the peaceful Edo period, 1603 to 1868, they became the stewards and chamberlains of the daimyo estates.