Constructed on the remains of a 7th century Chinese fortress, the Thăng Long Imperial Citadel was built on strategic reclaimed river lands on the lower Red River Delta and for nearly 13 centuries, remained the regional powerhouse of Northern Vietnamese political & military domination. Shortly after his ascension to the throne, Emperor Lý Thái Tổ declared a royal decree in the year 1010, to move the capital from Hoa Lư and establish a new Imperial City for the Lý Dynasty.