On the night of 21 July 1917, the Allied forces launched one of the most aggressive airstrikes of World War I on Roeselare. The city was bombarded with high-explosive and incendiary bombs, inflicting massive damage on a great number of buildings including the Klein Seminarie, the Broederschool, the fire station and the gas factory.

Apart from material damage, a considerable number of German soldiers and civilians were wounded or killed in the airstrike. On the same night, only a few hours after the attack on Roeselare, the castle of Staden was completely demolished by Allied bombs, killing 19 German officers and their staff.