For much of the war, the opposing armies on the Western Front were at a stalemate, with a continuous line of trenches stretching from the Belgian coast to the Swiss border. In essence, the Allied objective from early 1915 was to break through the German defences into the open ground beyond and engage the German army in a war of movement.
The Arras offensive was conceived as part of a plan to bring about this result. It was planned in conjunction with the French High Command, who were simultaneously embarking on a massive attack (the Nivelle Offensive) about eighty kilometres to the south.
The aim of this combined operation was to end the war in forty-eight hours. At Arras the Allied objectives were to draw German troops away from the ground chosen for the French attack and to take the German-held high ground that dominated the plain of Douai.