Silla observed Tang's seisaku (calendar) since it was charged with the use of its own era name by Taizong (the second emperor) of the Tang dynasty, but during the first half of Goryeo era, the era name of the Chinese dynasty and that of Goryeo's own were alternately used.
新羅は唐の太宗に国内で独自の年号を用いていることを咎められて以降唐の正朔を守っていたが、高麗前期には中国王朝の年号と高麗独自の年号を交互に使用していた。