Complex sentence: In 1918 the battalion helped to stop the German spring offensive in March and April, before participating in the great Allied offensive of 1918 that eventually brought about an end to the war, launched near Amiens on 8 August 1918.
Split into simpler sentences: In 1918 the battalion helped to stop the German spring offensive in March and April. The battalion subsequently participated in the greatest Allied offensive of 1918, launched near Amiens on 8 August 1918.