within the court. Lý Thần Tông was crowned under the supervision of Lê Bá Ngọc, a powerful eunuch. Lê Bá Ngọc adopted a son of the emperor's mother named Đỗ Anh Vũ. During the reign of Lý Thần Tông, Suryavarman II of the Khmer Empire launched an attack on Đại Việt's southern territories in 1128. In 1132 he allied with Cham king Jaya Indravarman III and briefly seized Nghệ An and pillaged Thanh Hoá. In 1135 Duke Đỗ Anh Vũ raised an army and repelled the Khmer invaders. After the Chams refused to support in 1137, Suryavarman II abandoned his incursions on Đại Việt and launched the invasion of Champa. At the same time, Lý Thần Tông began suffering a fatal illness, according to an inscription, and he died in the next year, leaving the infant Lý Thiên Tộ who became Emperor Lý Anh Tông (r. 1138–1175) under Đỗ Anh Vũ's patronage. After Đõ Anh Vũ died in 1159, another powerful figure named Tô Hiến Thành stepped into the role of guarding the dynasty until 1179. In 1149, Javanese and Siamese ships arrived Vân Đồn to trade. The sixth son of Lý Anh Tông, Prince Lý Long Trát was crowned in 1175 as Lý Cao Tông (r. 1175–1210). By the 1190s, more outsider clans were able to penetrate and infiltrate the royal family, weakening further the Lý authority. Three powerful aristocratic families–Đoàn, Nguyễn, and Trần (descendants of Trần Emperors, a Chinese emigre from Fujian) emerged in the court and contested on behalf of the royals. In 1210, Lý Cao Tông's eldest son Lý Sảm became Emperor Lý Huệ Tông (r. 1210–1224) of Đại Việt. In 1224, Lý Sảm appointed his second princess Lý Phật Kim (Empress Lý Chiêu Hoàng) as successor while he abdicated and became a monk. Finally, in 1225 the Trần leader Trần Thủ Độ sponsored a marriage between his eight-year-old nephew Trần Cảnh with Lý Chiêu Hoàng, that means the Ly would give up power to the Trần, and Trần Cảnh became Emperor Trần Thái Tông of the new dynasty of Đại Việt. The young Trần Thái Tông centralized the monarchy, organized the civil examination on the Chinese model, built Royal Academy and Confucian Temple, constructed and repaired the delta dikes during his reign. In 1257, the Mongol Empire under Möngke Khan who was waging a war to conquer the Song Empire, sent envoys to Trần Thái