Belgian 1st Infantry Brigade, also known by the name of its commander as the “Brigade Piron,” began as miscellaneous small elements in the United Kingdom, expanded to a “fusilier” battalion by the end of 1940, mustered a pair of such battalions in 1941, and in January 1943 assumed the official brigade designation. Various schemes were considered during this time for utilizing the brigade overseas, but it was decided to reserve it for the actual liberation of Belgium.

The brigade landed in Normandy in August and served with British 6th Airborne Division under Canadian 1st Army, advancing to Le Havre by the beginning of September. It was then transferred to British 1st Army and advanced to Brussels. Withdrawn from the line in November, the brigade reorganized, expanded, and re-entered the line with Canadian 1st Army in April, but with its 2nd Battalion detached to Walcheren Island.