sentences:  After overthrowing the Chinese government in Vietnam and founding the Ngô Dynasty, Ngô Quyền transferred the capital to Cổ Loa citadel, the capital of Âu Lạc, the ancient Vietnamese kingdom, thus affirming the continuity of the traditions of the Lạc Việt people.From this time, Ngô Quyền reclaimed Vietnamese independence and was proclaimed as King (Tiền Ngô Vương) of An Nam in 939.Ngô Quyền's immediate heirs proved unable to maintain a unified state.