Who ruled
- Byzantium Heraclius 610–641
- First Göktürk Khaganate Ilig Khan 620–630 · Töles Khan 620–630
- Western Göktürk Khaganate Tong Yabgu 618–630
And beyond the steppe
Eastern steppe
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Environment · Late Antique Little Ice Age: the cold phase the Altai tree rings define from 536 to about 660 (536–660)
Climate and the steppe empires · First Göktürk Khaganate · Avars
The coldest decade in the Altai is the 540s
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Environment · Lake Telmen stands 4.8 metres above its present level, a humid phase before the drying that follows (600–700)
Western steppe
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Tong Yabgu promises to march with the Tang against Ilig in the winter; Ilig, afraid, makes peace with him
China
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Economy · The Tang cavalry grows from five thousand horses to more than seven hundred thousand, supplied by the Göktürks (618–650)
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Ilig's riders with Liu Heita surround and kill the Tang general Li Da'en; Ilig raids Fenzhou with fifty thousand horse
Arabia and the caliphate
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Culture · The community of Muhammad moves from Mecca to Medina; the year later becomes the first of the Islamic era
