The dynasty established by Ngo Quyen lasted fewer than thirty years, however, and was overthrown in 968 by a local chieftain, Dinh Bo Linh, who reigned under the name Dinh Tien Hoang. He brought political unity to the country, which he renamed Dai Co Viet (Great Viet). The major accomplishments of Dinh Bo Linh's reign were the establishment of a diplomatic basis for Vietnamese independence and the institution of universal military mobilization. He organized a 100,000-man peasant militia called the Ten Circuit Army, comprising ten circuits (geographical districts). Each circuit was defended by ten armies and each army was composed of ten brigades. Brigades in turn were made up of ten companies with ten ten-member squads a piece. After uniting the Vietnamese and establishing his kingdom, Dinh Bo Linh sent a tributary mission to the newly-established Chinese Northern Song dynasty (A.D. 960-1125). This diplomatic maneuver was a successful attempt to stave off China's reconquest of its former vassal. The Song emperor gave his recognition to Dinh Bo Linh, but only as "King of Giao Chi Prefecture," a state within the Chinese empire. Not until the rise of the Ly dynasty (1009-1225), however, did the Vietnamese monarchy consolidate its control over the country.