King Ramathibodi I founds the capital of Ayutthaya, beginning a Siamese kingdom that lasts over four centuries.
Fa Ngum unites the Lao principalities into the kingdom of Lan Xang ("Million Elephants"), the forerunner of modern Laos.
Cham forces under King Po Binasuor (Chế Bồng Nga) sack the Đại Việt capital Thăng Long.
Nguyễn Trãi, scholar, poet and strategist of the Lam Sơn uprising, is born.
Retired emperor Trần Nhân Tông, founder of the Trúc Lâm school of Zen Buddhism, dies on Mount Yên Tử.
Princess Huyền Trân marries King Jaya Simhavarman III of Champa, who cedes the districts of Ô and Lý (around modern Quảng Trị and Huế) to Đại Việt.
Hồ Quý Ly builds the stone citadel of Tây Đô in Thanh Hóa, later a UNESCO World Heritage Site (2011).