From December 1936 to January 1937, Republican and Nationalist forces fought the Battle of the Corunna Road, a series of engagements along the road connecting Madrid to the northwest. The battle was part of the wider siege of Madrid, with the Nationalists attempting to cut the city's supply lines and the Republicans defending the vital corridor. The fighting was brutal and inconclusive, with both sides suffering heavy casualties, but the Republicans managed to hold the road, keeping Madrid supplied through the winter.

The Battle of the Corunna Road was chronicled in the war diaries and poems of International Brigade volunteers, who described the freezing conditions and relentless shelling. The battle also inspired the song 'Jarama Valley,' which became an anthem of the International Brigades and was later adapted by folk singers around the world. The poetry of this period increasingly focused on the grim reality of trench warfare, moving away from the early romanticism of the conflict.