Anping Castle, also known as Orenz City, Geranjah City, King City, Anping City, Taiwan City, is a fortress once existed in Tainan City, Taiwan. Originally built in 1624, it is the earliest fortress building in Taiwan. Since the founding of the city, it has been the center of Dutch rule of Taiwan and the residence of the rulers of the Zheng Dynasty. Anping Castle has two sites - "the remains of Taiwan City" and "the walls of Geranjah City and the architectural remains of the city".