<P> Overpopulation and land shortages stimulated a Vietnamese expansion south . In 1471, Le troops led by king Lê Thánh Tông invaded Champa and captured its capital Vijaya . This event effectively ended Champa as a powerful kingdom, although some smaller surviving Cham states lasted for a few centuries more . It initiated the dispersal of the Cham people across Southeast Asia . With the kingdom of Champa mostly destroyed and the Cham people exiled or suppressed, Vietnamese colonization of what is now central Vietnam proceeded without substantial resistance . However, despite becoming greatly outnumbered by Vietnamese settlers and the integration of formerly Cham territory into the Vietnamese nation, the majority of Cham people nevertheless remained in Vietnam and they are now considered one of the key minorities in modern Vietnam . Vietnamese armies also raided the Mekong Delta, which the decaying Khmer Empire could no longer defend . The city of Huế, founded in 1600 lies close to where the Champa capital of Indrapura once stood . In 1479, King Lê Thánh Tông also campaigned against Laos in the Vietnamese--Lao War and captured its capital Luang Prabang, in which later the city was totally ransacked and destroyed by the Vietnamese . He made further incursions westwards into the Irrawaddy River region in modern - day Burma before withdrawing . At his withdrawal, Vietnam extended in what would be considered as "the first Southeast Asian Empire" and perhaps, one of the most powerful nation in Asia . </P> <P> The Lê dynasty was overthrown by its general named Mạc Đăng Dung in 1527 . He killed the Lê emperor and proclaimed himself emperor, starting the Mạc dynasty . After defeating many revolutions for two years, Mạc Đăng Dung adopted the Trần dynasty's practice and ceded the throne to his son, Mạc Đăng Doanh, and he became Thái Thượng Hoàng . </P> <P> Meanwhile, Nguyễn Kim, a former official in the Lê court, revolted against the Mạc and helped king Lê Trang Tông restore the Lê court in the Thanh Hóa area . Thus a civil war began between the Northern Court (Mạc) and the Southern Court (Restored Lê). Nguyễn Kim's side controlled the southern part of Annam (from Thanhhoa to the south), leaving the north (including Đông Kinh - Hanoi) under Mạc control . When Nguyễn Kim was assassinated in 1545, military power fell into the hands of his son - in - law, Trịnh Kiểm . In 1558, Nguyễn Kim's son, Nguyễn Hoàng, suspecting that Trịnh Kiểm might kill him as he had done to his brother to secure power, asked to be governor of the far south provinces around present - day Quảng Bình to Bình Định . Hoang pretended to be insane, so Kiem was fooled into thinking that sending Hoang south was a good move as Hoang would be quickly killed in the lawless border regions . However, Hoang governed the south effectively while Trịnh Kiểm, and then his son Trịnh Tùng, carried on the war against the Mạc . Nguyễn Hoàng sent money and soldiers north to help the war but gradually he became more and more independent, transforming their realm's economic fortunes by turning it into an international trading post . </P> <P> The civil war between the Lê / Trịnh and Mạc dynasties ended in 1592, when the army of Trịnh Tùng conquered Hanoi and executed king Mạc Mậu Hợp . Survivors of the Mạc royal family fled to the northern mountains in the province of Cao Bằng and continued to rule there until 1677 when Trịnh Tạc conquered this last Mạc territory . The Lê kings, ever since Nguyễn Kim's restoration, only acted as figureheads . After the fall of the Mạc dynasty, all real power in the north belonged to the Trịnh lords . Meanwhile, the Ming court reluctantly decided on a military intervention into the Vietnamese civil war, but Mạc Đăng Dung offered ritual submission to the Ming Empire, which was accepted . </P>

What was the name of the social and political system that held japan together from 1400 to 1800