This letter was sent from Buckingham Palace in 1918 to a repatriated prisoner of war. It was one of copies that were probably received by thousands of men all over the country.
In this case it was sent to a private in the Worcestershire Regiment who, along with his brother, had been captured by the Germans on March 21st, 1918, the first day of their spring offensive around St Quentin in France. That was to be the last major action of the war launched by the Germans and they made significant territorial gains ahead of full-scale American involvement in the war.
Unfortunately, some of the sentiments expressed in this George V letter did not match what the ex-PoWs experienced on their return, and in Luton discontent among ex-servicemen generally ultimately culminated in the Peace Day riots in July 1919.