In the late 12th century, warrior Edo Shigetsugu was the first to build a fortification on the current Imperial Palace grounds. In 1457, the last of the Edo clan surrendered to Ōta Dōkan, a Japanese samurai (military noble). He then built the huge Edo Castle (Edo-jo) encircled by a system of moats. One of the few remnants of his construction is pictured on the left along Hamaguri Moat overlooking Kikyo-mon Gate. On the right is a watchtower (keep) named Tatsumi-yagura. During the Edo Period (1603 – 1867), Tukugawa shoguns occupied the castle while the surrounding city of Edo became the world’s largest. In 1868, when Meiji the Great became emperor, he renamed the city Tokyo (meaning eastern capital) and converted Edo Castle into the Imperial Palace.