It was also during this period that the Trần kings waged many wars against the southern kingdom of Champa, continuing the Viets' long history of southern expansion (known as Nam Tiến) that had begun shortly after gaining independence from China. Often, they encountered strong resistance from the Chams. Champa troops led by king Chế Bồng Nga (Cham: Po Binasuor or Che Bonguar) killed king Trần Duệ Tông in battle and even laid siege to Đại Việt's capital Thăng Long in 1377 AD and again in 1383 AD. However, the Trần Dynasty was successful in gaining two Champa provinces, located around present-day Hue, through the peaceful means of the political marriage of Princess Huyền Trân to a Cham king