The Crusade of Nicopolis was launched to relieve the city, but it was decisively defeated by the Ottomans. In 1399, a French expeditionary force under Marshal de Boucicaut arrived, but was unable to achieve much. The situation became so dire that in December 1399 the Byzantine emperor, Manuel II Palaiologos, left the city to tour the courts of Western Europe in a desperate attempt to secure military aid.