Life
Kul Tigin (684–731) was a general and a prince of the Second Turkic Khaganate. He was a second son of Ilterish Qaghan and the younger brother of Bilge Qaghan. He was seven years old when his father died. Thats why his uncle Qapaghan became new khagan. During the reign of Qapagan Khaghan, Kul Tigin and his older brother earned reputation for their military prowess.
War against rebels
Kul-Tigin defeated Turkic tribes that rebelled against Turkic Khaganate with his elder brother Bilge. They defeated Yenisei Kirghiz, Turgesh, and the Karluks, extending the Kaganate territory all the way to the Iron Gate south of Samarkand. They also subjugated all nine of the Tokuz Oguz (Uyghur) tribes. He helped his uncle Qapaghan with his elder brother Bilge, in the wars. In 711, he participated in Battle of Bolchu, which was disastrous for rebel tribes. Tonyukuk and Kul-Tigin faced against 100.000 men of rebel Turkic tribes Turgesh, Sir-Turdush and Oghuz. Tonyukuk and Kul-Tigin had only 20.000 men. But Kul-Tigin was such a warrior that defeated 100.000 men with 20.000 men.
Battle of Lingwu
In 705, Göktürk forces commanded by Bilge and Tonyukuk entered Lingwu county of Tang Dynasty. General Shazha of Tang faced against them with his army OF 50.000 men. Kul-Tigin commanded a unit in this Battle of Lingwu, in which he lost three horses. Kul-Tegin was wounded in this battle. But despite his injury, he got up and continued to fight. He fought so bravely that everyone was admiring him. He changed horses 3 times in this war. When his horse was killed by an arrow, he immediately found a new horse and continued to fight with it. He became a legend in this war by getting rid of hundreds of arrows shot by enemy soldiers.
This intelligence and courage of Kul-Tigin in battles also attracted the attention of the Tang Chinese. That's why they wrote him as "invincible warrior" in Chinese sources in 710. That's why we call him the Invincible Kul-Tigin. He has never lost a war in his life.
Battle of Ming Sha
Emperor Zhongzhong decided to gather an big army to destroy Göktürks and Qapaghan. He gather an army of 80.000 men. Those big Tang forces given under command of General Shazha Zhongyi faced against small numbers of Göktürk army in Ming Sha. Qapaghan Qaghan, Kul-Tigin and Bilge commanded Göktürk forces in this Battle of Ming Sha. Göktürks win a decisive victory in this battle and destroyed almost half of Tang army. Emperor trusted General Shazha again but he was defeated by Göktürks again.
Coup against Inel
Upon the death of Qapagan Khaghan, his son Inel Qaghan attempted to illegally ascend to the throne, defying the traditional Lateral succession law, but Kul-Tigin refused to recognize the takeover. Bilge and his brother Kul-Tigin carried out a coup against their cousin Inel. They killed him and made Bilge new khagan. Bilge's cousin Inel was killed by Kul-Tigin during struggle for the throne. Some writers say that the law of succession of Göktürks was that power passed from a ruler to his younger brothers before returning to his sons. Thats probably why Kul-Tigin didn't accepted Inel as khagan. Duoxifu, the uncle of Inel and also Bilge, defended him in this coup but he also was killed by Kul-Tigin. Thus the throne was first the right of Ilterish, eldest brother. Then Qapaghan, younger brother. Then, sons of Ilterish, eldest Bilge and then younger Kul-Tigin. Then Inel should be khagan after Bilge and Kul-Tigin. Inel, being Qapaghan's son, had no right on the throne. Inel and his supporters was killed by Kul-Tigin in 717. And Bilge became the khagan. Bilge appointed his brother Kul-Tigin to be Left Wise Prince, which made second most powerful person in realm.
Deadly war against the Dokuz Oghuz (Uyghurs)
According to Bilge Qaghan, the reason why the Uighurs were so aggressive towards the Göktürks was because of jealousy. The Uyghurs, especially at that time, were much stronger with the support of the Tang. The Uyghurs were already the Second Turkic Khaganate's biggest rivals. The Uyghurs had planned to attack the Göktürk high war headquarters and kill Kul-Tigin. While one group of soldiers was attacking the headquarters, the other groups would attack the other tents in the command headquarters together. This plan was devised by the Tang generals and the Uyghurs implemented it. But this plan didn't work. In this event, which lasted quite a long time, there were 5 major wars in total. Kul-Tigin defeated them before they could destroy the headquarters. However, this was Kul-Tigin's last legendary battle. By now, he had been injured so much in all the battles he participated in that his body could no longer take it. At the age of 47 he would become ill and die from these wounds.
Death
He died suddenly in 27 February 731. A stele in memory of Kul Tigin, which included inscriptions in both the Turkic and Chinese, was erected at his memorial complex at the present site of the Orkhon inscriptions. Kul-Tigin is also mentioned in the inscription erected in memory of his older brother Bilge Qaghan at the neighbouring site of Khöshöö-Tsaidam-1. His burial ceremony took place in 1 November 731. The head of the Kul Tigin sculpture in the Khöshöö-Tsaidam enclave in (Orkhon, in northern Mongolia) carries a bird with wings spread like an eagle, personifying a raven.
Bilge had arranged a very big funeral for him. Representatives from many countries, especially Tang, with whom Kul-Tigin fought many times, came to his funeral.