Here is a biography of Xue Rengui from
http://www.no1190.com/news/ReadNews.asp?NewsID=1720I'll translate it into english.
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(614~683) 中国唐朝名将。名礼,龙门(今山西河津)人。骁勇善骑射。贞观末,应募从军。唐军攻高丽,在安市城(今辽宁海城南)阻击援军时,他身着白衣奋战获胜,为太宗赏识,升为游击将军、北门长上。后又任右领军郎将。
(614- 683 AD), Tang's famous general. He's called Li and originated from Longmen (today's Shanxi Hejin). He excelled in horse riding and horse archery. During the late years of the Zhenguan reign (Emperor Taizong's time), he joined the Tang army. At that time, Tang was attacking Koguryo (in Korea). At the city of Anshi (today's Liao-ning province haichen city), he intercepted the Koguryo's assistance troop. He wore a white cloth and won the battle. After this victory, he was greatly admired by Emperor Taizong, and was promoted to "Guerilla General", later was appointed as the right-commander chief.
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高宗显庆中,辅助营州都督兼东夷都护程名振经略辽东,屡破高丽、契丹军,因功授左武卫将军。龙朔初,铁勒九姓袭扰,他率兵至天山;铁勒聚众10余万,先选数十骁骑挑战,他张弓三箭,射杀三人,其余请降。铁勒军溃逃,唐军追至碛北,获其叶护兄弟三人而还。乾封初,又参与攻高丽,因功授右威卫大将军兼检校安东都护。
During Emperor Gaozong's time, he assisted Yingzhou and Dongyi's governor to attack the Koguryo and Khitan army from Liaodong region. Later was assigned as left martial defense general. Later, the Tujue (Turks or "9 factions of Tiele 铁勒九姓) raided China. He led a force to Tianshan. The Turks had 100,000 troops and sent 10 cavalry on a duel with him, he used only 3 bows and killed 3 turks, which forced the Turks to surrender. The Turks fled and the Tang chased after them and captured Yehu and his brothers (Turks leader). After this campaign, he continued to led Tang's campaign against Koguryo, and after sacking Pyongyang, was later appointed as Youwei Great General plus Andong commandery's governor
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咸亨元年(670),吐蕃进扰,高宗以薛仁贵为逻娑道行军大总管,郭待封为副,率兵出击。因郭待封违背其意图,自率辎重前进,遭吐蕃军截击,辎重全部损失。薛仁贵退屯大非川(今青海共和境),被迫与吐蕃约和而还,免官为民。
In 670 AD, the Tubo (Tibetans) raided China. Emperor Gaozong assigned Xue Rengui as Luosa Path Infantry Great Commander, Guo Daifeng as second General to defend against Tubo's attack. Because of Guo Daifeng not listening to his command, they were routed by the Tubo and suffered major loss. Xue Renggui was forced to retreat to Dafeichuan, and was forced to buy peace with the Tubo. He was demoted to be a civilian.
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开耀元年(681),又被高宗起用,授瓜州长史;不久,授右领军卫将军,检校代州都督。永淳元年(682),突厥阿史德元珍反唐,他率兵出击。突厥军闻薛仁贵复起为将,自行退走,被唐军趁势追击而溃败。永淳二年(683)病卒。
In 681 AD, he was re-used by Empero Gaozong, appointed as Zhuzhou's military chief, re-assigned as right vanguard general. In 682 AD, Tujue (Turk) Ahsideyuan rebelled against Tang and he led the Tang's forces to attack Tujue. The Turks, after hearing that Xue was the general, retreated and was defeated by the Tang.
In 683 AD, Xue passed away.