In 2008, Vietnam Institute of Archaeology conducted an excavation at the south area of Thanh Nha Ho (Citadel of Ho dynasty). Three trenches were excavated next to the front and back of the citadel gate in the area of over 300m2. The unearthed relics were roads, yards built with rocks and the gate's foundation and bases. The artifacts collected were large in quantity and diversified, dating to the Tran - Ho, Le dynasties periods and some of them were from later period. The main results of this excavation preliminarily uncover traces of a road built with rocks running from the north gate through the south gate to Nam Giao open-air altar that is now scholarly known as "Con duong Hoang Gia" (Royal Road). They also reveal traces of rock-paved yard foundation inside and outside the south gate, where festivals were held as recorded in annals.