In the Battle of Loos (25 September–8 October 1915) the British First Army attacked between Grenay and Givenchy in support of the French Tenth Army attack further south against Vimy (the Third Battle of Artois). 1st Division was at Le Rutoire, in the middle of the line, and was tasked with the sector running from Northern Sap to the Hulluch road. The division's assaulting brigades were the 1st - where the two Guards battalions had in August been replaced by 10th Battalion Gloucestershire Regiment and 8th Battalion Royal Berkshire Regiment - and 2nd, with 3rd Brigade in divisional reserve behind the line.