The Spring Offensive of the German Army on the Western Front had begun on 21 March 1918 with Operation Michael and had petered out by July. The Germans had advanced to the River Marne, but failed to achieve their aim of a victory that would decide the war. When Operation Marne-Rheims ended in July, the Allied supreme commander Ferdinand Foch ordered a counter-offensive, which became known as the Second Battle of the Marne. The Germans, recognising their untenable position, withdrew from the Marne to the north. For this victory, Foch was granted the title Marshal of France.
After the Germans had lost their forward momentum, Foch considered the time had arrived for the Allies to return to the offensive. The American Expeditionary Force (AEF) under General John J. Pershing was present in France in large numbers and invigorated the Allied armies with its extensive resources.:472 Pershing was keen to use his army as an independent force. The British Expeditionary Force (BEF) had also been reinforced by large numbers of troops returned from the Sinai and Palestine campaign and the Italian front and replacements previously held back in Britain by Prime Minister David Lloyd George.:155
A number of proposals were considered and Foch agreed on a proposal by Field Marshal Sir Douglas Haig, commander-in-chief of the BEF, to strike on the River Somme, east of Amiens and south-west of the site of the 1916 Battle of the Somme, to force the Germans away from the vital Amiens–Paris railway.:472 The Somme was chosen because it remained the boundary between the BEF and the French armies, along the Amiens–Roye road, allowing the two armies to cooperate. The Picardy terrain provided a good surface for tanks, which was not the case in Flanders, and the defences of the German 2nd Army under General Georg von der Marwitz were relatively weak, having been subjected to continual raiding by the Australians in a process termed peaceful penetration.