Analysis of information sources in references of the Wikipedia article "மங்கோலியர்களின் கீவ உரூசு மீதான படையெடுப்பு" in Tamil language version.
The Mongols invaded the Russian steppes at this time, reaching the Crimea before turning back at the Khan's orders. The youngest son of Genghis, Tului, was given the special task of destroying walled cities during this campaign, employing the Chinese engines
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