The 7th Medium Regiment, Royal Canadian Artillery, was one of six Canadian medium regiments that saw service in Britain and continental Europe in the Second World War, the others being the 1st, 2nd, 3rd, 4th, and 5th Medium Regiments. (There was no 6th Medium.) The 1st, 2nd and 5th Mediums served in Italy, while the 3rd, 4th, and 7th were in northwest Europe. Three of these units (1st, 4th, and 7th) were each equipped with sixteen guns, firing 100-pound shells, while the other three had guns firing 60-pound shells. Medium regiments were not part of the artillery component of the individual infantry or armoured divisions as were most field regiments (25-pounder guns) but were classed as "Army" troops and were available to support any formation which needed the fire of heavier guns. 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). In the period from then until February 1941, during which time the regiment was at Petawawa, there were a number of organizational changes from which emerged the 7th Army Field Regiment, RCA, consisting of the 12th, 45th and 97th Batteries. The 7th continued its training at Petawawa and in New Brunswick until November 1941, when it went overseas to England, where it spent over two and a half years in constant training. 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. In the process it became a two-battery regiment, and the 97th Battery was disbanded, most of its personnel, however, being absorbed by the other two larger batteries. 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. The 7th Medium fired its first round in anger at Rots, near Caen, Normandy, shortly after 18:00 on 13 July