Khan Kotrag was the founder of Volga Bulgaria. He was the son of Kubrat who left Great Bulgaria after the death of his father. His successors reached the lands of modern Tatarstan and established a state during 7-9 centuries and recognised Islam as the official religion in 922 AD during the visit of Baghdad khalifat ambassador Ibn Fazlan and remained independent up until the 13th century, when it was conquered by the Batu-khan hordes of Mongolic and Turkic people widely known as Mongol-Tatars. The country's capital was called "Bulgar" or "Great Bulgar".
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