The Battle of Lys was part of the 1918 German Spring Offensive ordered by Luderndorff in a final attempt by the Germans to break the Allied lines around Ypres. The Battle of Lys can go by numerous titles and has been called the Fourth Battle of Ypres, the Lys Offensive and the Third Battle of Flanders.
By the Spring of 1918, the Germans knew that they faced a major problem on the Western Front. Since the American declaration of war, American soldiers had arrived in Western Europe in very large numbers. The German High Command knew that these numbers would only dramatically increase given time. The Spring Offensive was an attempt to defeat the Allies before the full might of the Americans reached Western Europe.
The aim of the Battle of Lys from the German point of view was to capture Ypres (Ieper) and the surrounding high ground around Messines.
The River Lys formed a barrier between two Allied armies.
The First Army commanded by General Horne was south of the river while the Second Army commanded by General Plumer was to the north.
The Germans planned to attack the First Army south of the river before moving northwest.
The attack started on April 9th 1918 following a two-day artillery bombardment. The German Sixth Army attacked.
At Nueve Chapelle they came across 20,000 Portuguese soldiers from the 2nd Portuguese Division who were commanded by General Gomes da Costa, a future President of Portugal. These troops were due to be relieved from front line duty the day the attack started. Facing them were 50,000 German troops. Short of officers and equipment, their resistance was short-lived and they retreated five miles suffering 7,000 casualties killed, wounded and missing. This gave the Germans all the incentive they needed as they had advanced much further into the Allied line than previously expected for that day.
General Horne was forced to pull back as well as he had to cover the gap created by the Portuguese withdrawal. However, the British 55th Division based to the south of the Portuguese managed to halt a German advance in this area.
Another German attack on April 10th led to the capture of what was left of the village of Messines. While the ruins of the village may not have accounted for much, the Germans greatly benefited by the height that the Messines Ridge gave to them.
On April 12th the Germans made a concerted attempt to capture Hazebrouk, a major Allied logistics centre. The capture of this town would have been a major blow for the Allies. However, the town held out when the Australian 1st Division halted the German advance five miles from the town centre.
The German advance was such that Field Marshal Haig asked the new General-in-Chief Allied Forces, Marshal Foch, for reinforcements. Initially Foch was unwilling to send reinforcements but on April 14th he did just this. However, between April 10th and April 14th, British troops had been in a precarious position and Haig issued his famous “backs to the wall" order:
“With our backs to the wall, and believing in the justice of our cause, each of us must fight on to the end."
The arrival of reinforcements eased Haig’s plight. While the Germans continued to advance and took several key targets (Mount Kemmel and the Scherpernberg – both of which gave the Germans height advantage), the attack had started to stall by April 29th with the arrival of French reinforcements. Luderndorff called a halt to the attack. The gains at the Battle of Lys were the last the Germans made in World War One.
The Battle of Lys cost the Germans dearly in terms of men lost. While the arrival of thousands of US troops boosted Allied manpower, the Germans could not afford such losses despite men arriving from the Eastern Front. The Germans lost 120,000 killed, wounded or missing. While the initial territorial gains in the battle may have boosted German confidence in their High Command, they could not cope with their overall losses.
British and French losses were on a similar scale. However, the steady inflow of US troops meant that the Allies could cope with this loss.