Zizhi Tongjian, vol. 185. However, Emperor Gaozu's biography in New Book of Tang recorded the date as the geng'wu day of that month, corresponding to 19 June 618 in the Julian calendar.
Zizhi Tongjian, vol. 187. However, Emperor Gaozu's biographies in both Books of Tang recorded the day as the yi'si day of that month, corresponding to 25 May 619 in the Julian calendar.
