... at the end of the eighth century when the title of Bố Cái Ðại Vương (Father and mother of the people) was given by his successor and his subjects to Phùng Hưng , who, in 791,overthrew the then ... advantage of the Tây Sơn , revolt in the South, the Trịnh attacked and took Phú Xuân , the capital of the Nguyễn in the South.However, both the Trịnh and the Nguyễn were finally overthrown by the ... concerned, the official use of the two nôm characters Bố and Cái late in the eighth century and that of the nôm character Cồ in the tenth century are fair indications that some patterns of Chữnôm...