Battle of Qianshui Plain (618) — the same event in Old Book of Tang and New Book of Tang
Old Book of Tang: Li Shimin crushed Xue Renggao at the Qianshui Plain, forced his surrender, and pacified Longyou.; New Book of Tang: After a…
What each source says
Li Shimin crushed Xue Renggao at the Qianshui Plain, forced his surrender, and pacified Longyou.
秦王大破薛仁杲於淺水原，降之，隴右平。
Location: 舊唐書 卷1 武德1年
After a sixty-day standoff at Gaoqi Castle, Xue Rengao surrendered.
仁杲乃出降
Location: 新唐書 卷002 太宗 武德1年8月