large part of the Spanish Republican exiles in France; many of them joined the French Resistance. By 1944, with the German forces in retreat, many of the guerrillas refocused their fight towards Spain. Despite the failure of the invasion of the Val d'Arán that year, some columns continued to progress into the Spanish interior and to connect with the groups that had remained in the mountains since 1939. The apogee of guerrilla action was between 1945 and 1947. After this, the repression from the Franco government intensified, and one by one the groups were destroyed. Many of their members died or were incarcerated. Others escaped to France or Morocco. In 1952, the last important contingents evacuated from Spain. After that, those who resisted in the forested and mountainous regions refusing to choose either exile or surrender, fought only for their own survival. Beginnings The origins of the maquis in Spain lie with those who fled the advancing forces of Franco's Nationalists. The insecurity engendered by the repressive tactics of the Nationalist insurgency turned their political opponents—even many who were not politically active but simply known to sympathize with the republic—into fugitives. At first many hid in relatives' homes, but some sought refuge in the mountains. Their numbers were enhanced by deserters and by escapees from prisons and concentration camps. These constituted the nucleus of those who decided to keep fighting from the forests and mountains. The political character of the guerrillas was as varied as that of the Popular Front, containing communists, socialists, and anarchists. Despite the diverse ideologies, due to the organizational persistence of the Communist Party of Spain until 1948, the Communists dominated the other currents. XIV Cuerpo de Ejército During the war, the idea of the possibility of a guerrilla war at the rearguard of Franco's Nationalists was proposed. The idea came to fruition at the initiative of Juan Negrín, at the time head of the Republican government and of the Ministry of Defense. He created the XIV Cuerpo de Ejército Guerrillero (Guerrilla Army Corps) in October 1937. This name was used for the Basque section of the Spanish Republican Army until the collapse of the front in the north. The short-term objectives of this Corps were the interruption of the communications and supply lines to the Nationalist troops, and the carrying out of special operations. In the long term, they were to continue the war against