In October 1914 Greman forces captured Vimy Ridge, French forces were defending the area until February 1916 when British forces took over, Candian forces joined the British troops in January 1917
The main assult in which Allied forces took back Vimy Ridge started on Easter Monday, 9 April 1917. The weather was cold with sleet and snow, which combined with a north-westerly wind created a great advantage of snow blowing in the faces of defending German troops.
The attack started with an artillery bambardment from British and Canadian forces throughout the night of the 8th and the early hours of the 9th. Throughout the next three days Bristish and Canadian troops advanced forward taking out German strongholds and trenches. On 12 April 1917 at 6:00pm Allied forces had recaptured Vimy Ridge.
More information about The Battle of Vimy Ridge.