The Catalonia Offensive (, ) was part of the Spanish Civil War. The Nationalist Army started the offensive on 23 December 1938 and rapidly conquered Republican-held Catalonia with Barcelona (the Republic's capital city from October 1937). Barcelona was captured on 26 January 1939. The Republican government headed for the French border. Thousands of people fleeing the Nationalists also crossed the frontier in the following month, to be placed in internment camps. Franco closed the border with France by 10 February 1939.
Background
After its defeat at the Battle of the Ebro the Republican Army was broken and would never recover. The Republicans had lost most of their armament and experienced units. Furthermore, in October 1938 the Republican government agreed to withdraw the volunteers of the International Brigades. On the other hand, the Nationalists received new supplies of ammunition, weapons and aircraft from Germany. Furthermore, after the Munich Agreement, the hope of an intervention of the Western democracies in order to aid the Republic against Germany and Italy vanished. France had closed the frontier again in mid-June 1938 and frozen Republican financial assets in French banks.
Opposing forces
Nationalists
At the beginning of December, the nationalist faction concentrated an Army Group, the Army of the North, of 300,000–340,000 men led by the general Fidel Dávila in order to conquer Catalonia. The Nationalists assembled their best divisions all along the front from the Pyrenees to the Mediterranean. Along the Segre the Nationalists deployed Muñoz Grandes's Army of Urgel, Garcia Valiño's Army of Maestrazgo and Moscardo's Aragon Army; in the confluence of the Segre with the Ebro Gambara's Italian Cuerpo Legionario Italiano of four divisions (55,000 men) and Solchaga's Army Corps of Navarra; and in the Ebro the Yagüe's Moroccan Corps. The Nationalists also had, according to Beevor, 300 tanks, more than 500 aircraft (among them the Bf 109E and Heinkel 112 fighters) and 1,400 cannon.
Republicans
Opposing the Nationalists, the Republicans had Colonel Perea's East Army and Colonel Juan Modesto's Ebro Army under the command of General Juan Hernandez Saravia, commander of the Oriental Region's Army Group, with 220,000–300,000 men, many unarmed (Hernandez Saravia said that the Republican army had only 17,000 rifles for all Catalonia), 106 airplanes (most of them Chatos), 250 cannons and 40 tanks (many of them unserviceable due to shortage of spare parts). The Soviet government agreed to send to Catalonia a shipment of 250 aircraft, 250 tanks and 650 cannons, but the shipment did not reach Bordeaux until 15 January and only a small part of it crossed the border. Furthermore, because of the international isolation of the Republic and the lack of food (according to Beevor, in Barcelona the ration per day was down to 100 grams of lentils) the morale of the government troops and civil population in the Republican zone was very low. The people only wished the end of the war: "...just let it be over, it doesn’t matter how it ends, but let it end now."
Battle
Nationalist offensive
The Nationalist offensive was planned for 10 December but was postponed to 23 December. On 23 December the Italians and the Navarreses crossed the Segre at Mequinenza, broke the Republican lines, and advanced sixteen kilometres, but they were stopped by the V and XV Republican corps led by Lister on 25 December. On the left flank, Muñoz Grandes and Garcia Valiño advanced towards Cervera and Artesa, but they were blocked by the 26th Republican Division. On the south, Yagüe's troops were held back by the Ebro's floodwater. The Republicans had stopped the first Nationalist attack; nevertheless, they had lost 40 aircraft in the first ten days of the battle.
On 3 January Solchaga attacked Les Borges Blanques, Muñoz Grandes and Garcia Valiño occupied Artesa, and Yagüe crossed the Ebro. Moscardo attacked from Lleida and the Italians occupied Les Borges Blanques on 5 January. The same day, the Republican army started a surprise attack in Extremadura towards Peñarroya in order to divert Nationalist forces, but the offensive was halted after a few days and the Nationalist offensive in Catalonia continued. On 9 January the Moscardo's Aragon Army Corps joined Gambara at Mollerusa and broke the northern part of the front. The V and XV Republican Corps collapsed and retreated in disorder. On 15 January the Aragon and Maestrazgo Corps conquered Cervera and the Moroccan Corps after a one-day march of 50 km occupied Tarragona. By this day, the Nationalists had conquered a third of Catalonia, had taken 23,000 prisoners, and had killed 5,000 Republican soldiers.