The 7th Medium Regiment was raised in September 1939 with the mobilization of four Ontario militia field artillery batteries: the 12th (London), 45th (Lindsay), 97th (Walkerton) and 100th (Listowel).

A major change occurred in November 1943 when the regiment was converted from Field to Medium, and gave up its 25-pounders for the much bigger 5.5 inch.

The war for the 7th Medium became the real thing when it crossed the Channel in the second week in July 1944, and from then until the end of the fighting in the first week of May 1945 it took part in all the major battles and actions in which First Canadian Army was engaged: Normandy, the Seine crossing, the Channel ports (Boulogne and Calais), the Scheldt, Bergen op Zoom, Nijmegen salient, the Rhineland, the Rhine crossing, the advance through central and northern Netherlands, and finally across the Ems River into northwest Germany.

In Normandy, during Operation Totalize, on 8 August 1944, a group of American bombers dropped their ordnance right on top of the 7th medium regiment, 12th battery, Royal Canadian Artillery.

"The great problem on our side was road space, and it was while waiting in our gun positions, still firing at the retreating German forces, that the first disaster of the campaign befell us.

Bugler, was dedicated to Lieutenant Colonel H.C. Becher, commanding, 7th Regiment Fusiliers, London, Ontario.