Si Yabgu Khan

Si Yabgu Khan was a son of Tong Yabgu. After his father’s murder he became khan of the western Göktürks. At first he ruled beside the murderer, and then he ruled alone until 632.^[1] The Chinese histories name him for three things: his war against the murderer, his defeat by the Xueyantuo and the harshness that cost him his throne.^[2]

Accession

Before his accession he was Dieli Tegin.^[2] When his father was murdered, he fled from the murderer, Baghatur Khan, to Kangju.^[3] The Nushibi tribes had offered the title of khan to Nishu Bagha Shad. He declined it.^[4] Nishu fetched Dieli from Kangju and raised him as Yipi Boluo Si Yabgu Khan.^[3] The Zizhi tongjian enters this, with the murder, at the end of 628.^[5]

The Xin Tang Shu says that he and Baghatur divided the realm between them.^[6] They fought without pause. Both asked the Tang for a princess, and the emperor Taizong refused.^[3] The states of the Western Regions and the Tiele, who had served the western Göktürks, fell away.^[3] Si Yabgu was the son of the old ruler, and he won the people over. Many of Baghatur’s chiefs came to him.^[3] He attacked Baghatur and drove him to the Altai, where Nishu killed him.^[3] The tribes then raised Si Yabgu as great khan. The Zizhi tongjian enters his victory at the end of 630.^[5]

Reign and fall

As great khan he sent a large army north against the Tiele. The Xueyantuo met it and beat him.^[7] The Jiu Tang Shu calls him suspicious and harsh. It says that he was quick to believe slander and lacked the gift of command.^[8] The lesser khan Yili had served him best of all. Si Yabgu had him put to death with his whole clan.^[7] The histories give three reasons. The Jiu Tang Shu says that Yili was guiltless. The Xin Tang Shu says that Si Yabgu listened to slander. The Zizhi tongjian says that Yili was not of his clan.^[7] His lords were terrified.^[8]

He feared Nishu and plotted in secret to kill him. Nishu fled to Karashahr.^[2] A tarkan then conspired with the chiefs of the Nushibi against Si Yabgu. The Jiu Tang Shu calls this man Mobei, and the Zizhi tongjian calls him Shebei.^[9] Si Yabgu fled with light horsemen to Kangju and died there soon after.^[9] The Xin Tang Shu says that he died of grief.^[6] The Zizhi tongjian enters his flight in 632.^[10] The people fetched Nishu from Karashahr and made him khan.^[9]

In Xuanzang’s record

The Record of the Western Regions of the pilgrim Xuanzang tells a different end.^[11] At Balkh, it says, Si Yabgu Khan, the son of the Yabgu Khan of the Göktürks, had lately led out all his tribes and troops against the New Monastery outside the city to seize its treasures.^[11] He camped not far from it.^[11] In the night he dreamed that the god Vaisravana asked him what power he had to dare destroy the monastery. In the dream the god pierced him through with a long halberd.^[11] He woke with pain in his heart and sent in haste for the monks to make amends. He died before his messengers returned.^[11] Some scholars join the two accounts and have him die while he besieged Balkh.^[12] The same passage makes Si Yabgu the son of the Yabgu Khan. It is the ground for taking the khan whom Xuanzang met near Suyab for Tong Yabgu.^[13]

Name

乙毗缽羅肆葉護可汗ChineseJiu Tangshu 194
肆葉護可汗ChineseRecord of the Western Regions 1
咥力特勒ChineseJiu Tangshu 194

His title was 乙毗缽羅肆葉護可汗, Yipi Boluo Si Yabgu Khan, in the Jiu Tang Shu, the Tongdian, the Xin Tang Shu and the Zizhi tongjian.^[14] The Cefu yuangui writes Yipi Shaboluo Si Yabgu Khan.^[15] The element 葉護 in it is the title yabgu, as in his father’s name.^[16] His name as a prince, Dieli Tegin, is written 咥力特勒 in the Jiu Tang Shu and 咥利特勤 in the Tongdian.^[4]