During the Second Empire, foreign and mercenary soldiers became an important part of the Bulgarian army and its tactics. Since the very beginning of the rebellion of Asen and Peter, the light and mobile Cuman cavalry was effectively used against the Byzantines and later the Crusaders. For instance, fourteen thousand of them were used by Kaloyan in the battle of Adrianople. The Cumans were the empire's most effective military component. The Cuman leaders entered the ranks of Bulgarian nobility, and some of them received high military or administrative posts in the state. During the 14th century the Bulgarian army increasingly relied on foreign mercenaries, which included Western knights, Mongols, Ossetians or came from vassal Wallachia. Both Michael III Shishman and Ivan Alexander had a 3,000-strong Mongol cavalry detachment in their armies. In the 1350s, Emperor Ivan Alexander even hired Ottoman bands, as did the Byzantine Emperor. Russians were also hired as mercenaries.