 The Republicans fought fiercely, and the difficult terrain of the "Cordillera Cantabrica" provided excellent defensive positions.Solchaga's troops (33,000 men) occupied Llanes on September 5 and in the Battle of El Mazuco attacked the heights, held by the "CNT" workers from "La Felguera" (5,000 men).The Navarrese eventually took the valley and surrounding mountains, but only after 33 days of bloody combat.