As the infantry of the 1st Canadian Division and its accompanying armour closed up to the Hitler Line, the supporting guns had to move forward a number of times to keep within range. Forward Observation Officers and Artillery Representatives, previously allotted to the infantry and tanks, provided continuous close support, daring on the resources of the whole of the divisional artillery, with the fire of the 1st Canadian AGRA on call. To avoid the necessity of changing F.O.O.’s and representatives whenever their regiments came out of action to move, these remained forward with their affiliated brigades throughout, switching their wireless frequencies to the new unit whose guns they were now firing… More to come but at 3 am I'm going to call it a night! …By the afternoon of 19 May forward brigades had made contact with the outer defences of the Hitler Line, and early next morning General Leese issued orders for the Canadian Corps to attack and break the Line between Pontecorvo (on the left bank of the Liri) and the Forme d’Aquino. On the north side of the valley the 13th Corps was to maintain pressure on Aquino and to concentrate forward in readiness on the Canadians’ right once the break-through had been achieved. In his instructions for the operation, which was code-named “Chesterfield,”…. The supporting fire plan for “Chesterfield”called for a heavy programme of artillery preparation to be fired while the assault was being mounted….All the artillery available on call participated, and by midnight 19/20 May approximately one thousand rounds per hour were falling on known enemy strongpoints. During the next 72 hours some 400 guns, provided by the artillery of the 1st and 5th Canadian Divisions, the 1st Canadian AGRA, the French Expeditionary Corps, and the United States 13th Field Artillery Brigade, continued this bombardment at various timings and rates of fire.