They began the campaign in each territory by sending official envoys to request the capital city to surrender, join the Mongol family, and become the vassals of the Great Khan. If they agreed, the envoy offered protection to the new vassals from their enemies and allowed them to keep their ruling family and their religion. In return for such protections, the people had to agree to commit tribute of 10 percent of all wealth and goods to the Mongols. Few cities took the offer.
