Timur gained prominence as a military leader whose troops were mostly Turkic tribesmen of the region. He took part in campaigns in Transoxiana with the Khan of the Chagatai Khanate. Allying himself both in cause and by family connection with Qazaghan, the dethroner and destroyer of Volga Bulgaria, he invaded Khorasan at the head of a thousand horsemen. This was the second military expedition that he led, and its success led to further operations, among them the subjugation of Khwarezm and Urgench.