The Vietnamese are descendants of nomadic Mongols from China and migrants from Indonesia. According to mythology, the first ruler of Vietnam was Hung Vuong, who founded the nation in 2879 B.C. China ruled the nation then known as Nam Viet as a vassal state from 111 B.C. until the 15th century, an era of nationalistic expansion, when Cambodians were pushed out of the southern area of what is now Vietnam.