Goguryeo

Rouran epoch Göktürk epoch Uyghur epoch Kirghiz epoch

Rouran First Göktürk Tang rule Second Göktürk Uyghur Kirghiz Huns Western Göktürk Türgesh Karluk Khazar

Rouran 400–554
First Göktürk 552–630
Tang rule 630–682
Second Göktürk 682–744
Uyghur 744–840
Kirghiz 840–924
Huns 370–469
Western Göktürk 552–659
Türgesh 699–766
Karluk 766–800
Khazar 650–969

Goguryeo controlled the northern half of the Korean peninsula and the Liao country of southern Manchuria. It was the eastern neighbour of every steppe power from the Xianbei to the Göktürks. Its wars with China explain why the eastern frontier looks as it does in the century of the first khaganate.

The eastern edge of the steppe world

A Korean source reports that ten thousand Göktürks besieged towns on the Goguryeo frontier in 551. The kingdom and the khaganate shared the Khitan and the Tatabï as subjects and buffers between them. In that space the Khitan changed sides for two centuries.

Among the mourners who came to the funeral of the founders from the direction of the sunrise, the Kül Tegin inscription names a people it calls the Bökli.^[1] The most common identification equates them with Goguryeo. Elsewhere the inscription says that the Göktürks campaigned for the Chinese emperor eastward as far as the Bökli khan.^[1] The equation is an interpretation. The text does not state it.

The Sui and Tang campaigns

The Sui ruined themselves in their wars against Goguryeo. The empire sent four campaigns against it between 612 and 614, on a scale it could not bear. The risings that ended the dynasty began in the exhaustion these campaigns caused. The encirclement at Yanmen in 615 came the year after the last of them. The Sui Shu names the two together as the beginning of the end.^[2]

The Tang took up the same war and did no better at first. The campaign of 645 failed before the walls of Anshi. Goguryeo was destroyed only in 668, by a Tang army working with the southern Korean kingdom of Silla. Silla then took the peninsula for itself.

The eastern half of the frontier problem

The Chinese effort in Korea was the other half of the frontier problem that shaped Sui and Tang dealings with the steppe. A dynasty that spends four armies on the Liao has fewer to spend on the Ordos. Modern accounts treat both the collapse of the Sui and the Tang’s readiness to rule the steppe through Ashina clients rather than by garrison as parts of the same explanation.