Preliminary defensive actions in mid February were followed by "Operation Encore", a series of attacks in conjunction with troops of the 1st Brazilian Infantry Division, to dislodge the Germans from their artillery positions in the Northern Apennines on the border between Tuscany and Emilia-Romagna regions, in order to make possible the Allied advance over the Po Valley. While the Brazilian division was in charge of taking Monte Castello and "Castelnuovo" di Vergato, the 10th Mountain Division was responsible for the "Mount Belvedere" area, climbing nearby Riva Ridge during the night of 18 February and attacking mount "Della Torraccia" on 20 February. These peaks were cleared after four days of heavy fighting, as Axis troops launched several counterattacks in these positions.