The nomads of central Asia, who had produced great conquerors in the distant past, were little match for the disciplined armies of the 19th century. Raids by Muslim guerillas encouraged local Russian governors to take the initiative in subduing the central Asian khanates of Khiva and Bukhara. Envoys from Russia and Britain to Bokhara were treated with arrogance and contempt, and in 1848 two British officers were imprisoned and killed.