 Claiming to have seen a dragon ascending the Red River, he renamed the site Thăng Long (, "Soaring Dragon") – a name still used poetically to this day.Thăng Long remained the capital of Đại Việt until 1397, when it was moved to Thanh Hóa, then known as Tây Đô (), the "Western Capital".Thăng Long then became Đông Đô (), the "Eastern Capital."