The text mentions that Timur's army consisted of 'well-trained warriors bound by strict discipline'. What other groups were fighting for Timur, who were hoping to gain his favor if he won?

Analysis:

The text describes Timur's forces: 'Войско Тимура состояло из хорошо обученных / нов, связанных строгой дисциплиной. Е / ставе его войска сражались и волжские / гары, надеявшиеся на получение своб / в случае победы Тимура.' This translates to: 'Timur's army consisted of well-trained / warriors bound by strict discipline. In / the ranks of his army also fought Volga / Bulgars, hoping to receive his favor / in case of Timur's victory.'

Answer: Волжские булгары