Later, Nguyễn Huệ marched north and put down the rebellion in Tonkin. Huệ proclaimed himself as Emperor Quang Trung in 1788, and defeated Qing army in Battle of Ngọc Hồi-Đống Đa. Meanwhile, the civil war of Tây Sơn brothers had provided Nguyễn Ánh with the chance to go back to Cochinchina again. Nhạc's territory was eroded by Nguyễn lord. During his final years, he only controlled three provinces: Quy Nhơn (modern Bình Định), Quảng Ngãi and Phú Yên. He was described as "an old man who is resigned to the present state of affairs" by Nguyễn Huệ. Huệ was also worried about the future of Tây Sơn dynasty.