On June 17, 1917, the Corpo Expedicionario Portugues (CEP), or Portuguese Expeditionary Corps, goes into action for the first time in World War I, on the battlefields of Flanders on the Western Front.
With the outbreak of World War I in the summer of 1914, Portugal entered the war on the side of the Allies in order to secure international backing of its colonial holdings in Africa. While Portuguese participation in the war was at first limited to naval support, Portugal sent its first troops–an expeditionary force of two divisions, or some 50,000 men–to the Western Front in February 1917.
On June 17 of that year, the CEP saw its first action of the war, against the Germans in Flanders, Belgium. From the beginning of the fighting, the Portuguese troops, fighting alongside the British, were plagued by problems, including negative reactions to the poor rations and harsh weather on the battlefield and low morale due to the fact that they were fighting far from their native land, on behalf of a foreign cause. On April 9, 1918, the CEP saw action again against Germany near the town of Lys, during the major German offensive of that spring. During the Battle of Lys, one Portuguese division of troops was struck hard by four German divisions; the preliminary shelling alone was so heavy that one Portuguese battalion refused to push forward into the trenches. All told, the victorious Germans took more than 6,000 prisoners at Lys and were able to push through the Allied lines along a three-and-a-half mile stretch. By the time World War I ended, a total of 7,000 Portuguese soldiers had died in combat.