In mid-December Alexander became supreme commander of the Mediterranean Theatre. Clark took his place as commander of the Allied Armies in Italy (re-designated 15th Army Group) and command of U.S. Fifth Army was given to Lucian K. Truscott. In mid-February, as the winter weather improved, Fifth Army resumed its attacks on German artillery positions ("Operation Encore"). This time the IV Corps used two full infantry divisions to accomplish the mission: the Brazilian division, tasked with taking Monte Castello, Soprassasso and Castelnuovo di Vergato; and the newly arrived U.S. 10th Mountain Division, tasked to take Belvedere, Della Torraccia and Castel D'Aiano. Operation Encore began on 18 February and was completed on 5 March, preparatory to the final offensive in Italy.