The fate of the Spanish Republic was sealed at the battle of the Rio Ebro, which was a battle not only for ground, but for time. If the Republic could hold out long enough it might be rescued by the anti-Fascist forces in a forseeable European war, but the appeasement of HItler at Munich in September of 1938 dashed those hopes.
The Battle of the Ebro was the most costly confrontation of the Civil War, doubly so for the Republicans, as it came on the heels of two years of bitter-but-unsuccessful fighting, The confrontation on the Ebro looked promising at the beginning, as the Republican troops succeeded in crossing the river and advancing 25 kilometers.
But a counter attack by the Franco forces converted the struggle into a static battle of attrition, in which the Republican forces were destined to lose to Franco’s professional army. By January 1939 the people of Barcelona had given up hope of defending the city. Many of them said, “No matter how it ends, let it end now.” Soon masses of them were to join the lines of refugees headed for the French border on foot, some of them suffering cruel hardships crossing the Pyrenees in winter.
At this point the Republican president, Juan Negrin, facing a revolt led by his commander in Madrid, threw in the towel. He and his government abandoned the provisional Republican capital at Alicante for exile. The war was over and the Nationalist executions began. Some 200,000 Republicans were sent to prison where many were summarily executed and some spent the next 25 years.
See the video of The Spanish Civil War – Victory and Defeat (6/6) here: http://youtu.be/Qaxd3pU_UQI