this, Kubrat had made an alliance with Heraclius of the Byzantine Empire. He was baptized in 619. Kubrat died in the 660s and his territory, Old Great Bulgaria, was divided between his sons. Two of them were incorporated by the Khazars, one headed to Pannonia, and one became a subject of the Byzantines. The Bulgars in Pannonia revolted against the Pannonian Avars and migrated to Thessalonika by 679. There they formed the First Bulgarian Empire. Khazar The origin of the Khazars is unclear. According to Al-Masudi, the Khazars were called Sabirs in Turkic. Dunlop (1954) suggests a relation to Uyghurs, some of whom might have migrated west before 555 CE. Because imperial Chinese sources linked Khazars to Göktürks, others believe the Khazars were founded by Irbis Seguy, the penultimate ruler of the Western Turkic Khaganate, since the Hudud al-'Alam says the Khazar king descended from the Ansa, which has been interpreted as Ashina. By the mid-7th century, the Khazars were located in the North Caucasus, where they fought against the Umayyads constantly. Kyrgyz According to the Book of Tang, the Yenisei Kyrgyz were tall, red-haired, pale-faced, and green-eyed; black-eyed Kyrgyzes were claimed to be descendants of Han general Li Ling, presumably including the Kyrgyz Khagans who claimed such descent. It also notes that Kyrgyz women outnumbered men, both men and women wore tattoos, and they made weapons which they gave to the Turks. They practiced agriculture but did not grow fruits. The Kyrgyz lived west of Lake Baikal and east of the Karluks. According to the Book of Sui, the Kyrgyz chaffed at the domination of the First Turkic Khaganate. The Uyghur Khaganate also made war on the Kyrgyz and cut them off from trade with China, which the Uyghurs monopolized. As a result, the Kyrgyz turned to other channels of trade such as with the Tibetans, Arabs, and Karluks. From 820 onward, the Kyrgyz were constantly at war with the Uyghurs, until 840, when the Uyghur Khaganate was dismantled. Although the Kyrgyz managed to occupy some of the Uyghur lands, they had no great effect on the geopolitical configuration around them. The Chinese paid no heed to them other than to award them with some titles and reasoned that since the Uyghurs were no longer in power, there was no reason to maintain relations with the Kyrgyz any longer. The Kyrgyz themselves seemed to lack any interest in occupying