In June 1944, 20 Canadian soldiers were massacred in a garden at the abbey by members of the 12th SS Panzer Division Hitlerjugend over the course of several days and weeks.

[1][2] The perpetrators of the massacre, members of the 12th SS Panzer Division, were known for their fanaticism, the majority having been drawn from the Hitlerjugend or Hitler Youth.

[3] During the Normandy Campaign, Waffen-SS Standartenführer Kurt Meyer, commander of the 12th SS Panzer Division Hitlerjugend, used the Abbaye d’Ardenne for his regimental headquarters, as its towers gave a clear view of the battlefield.

Specifically the Geneva Convention pertaining to the Treatment of Prisoners of War stipulates in Part I: General Provisions - Art.

On 17 June, two more Canadian soldiers, Lieutenant Frederick Williams and Lance Corporal George Pollard, were also believed to have been killed at or around the Abbaye.

"[1] After liberating the Abbaye d’Ardenne on 8 July, members of the Regina Rifle Regiment discovered the body of Lieutenant Williams; Lance Corporal Pollard was never found.

The bodies of those killed on 7 and 8 June were not found until the winter and spring of 1945, when inhabitants from the abbey accidentally discovered remains throughout the premises.

[9] Macdonald eventually managed to have Helzel verify his original statement, thus helping to establish Meyer’s guilt.

He maintained that his column of prisoners arrived at the Abbaye Ardenne on 7 June, after which military police demanded 10 volunteers step forward.

After the officer and guards left, Jesionek and three fellow drivers examined the bodies, all lying in the garden and surrounded by blood.

According to Jesionek, the Canadians realized what was happening, each prisoner shaking hands with his comrades before walking to the garden and being shot.

These claims were refuted by French teenagers, however, who lived in the Abbaye and testified that no bodies were visible in the garden when they went there the day after the murders.

Meyer was found guilty of inciting his troops to commit murder and of being responsible as a commander for the killings at the Abbaye; he was acquitted on the second and third charges.