Who ruled
- Byzantium Heraclius 610–641
- Western Göktürk Khaganate Si Yabgu Khan 628–632 · Nishu Bagha Shad 632–634
- Xueyantuo Khaganate (Syr Tardush) Yinan Khan 628–645
And beyond the steppe
- China Tang Taizong 626–649
- Iran Sasanian Yazdegerd III 632–651
- Korea Goguryeo Yeongnyu 618–642
- Byzantium Heraclian Heraclius 610–641
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)
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)
Arabia and the caliphate
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Muhammad dies; within ten years the armies of the new state hold Syria, Egypt and Iraq
