Developed by Generalleutnant (Lieutenant General) Erich von Manstein, the plan greatly modified the original 1939 versions of the invasion plan, Fall Gelb (Case Yellow) by Franz Halder, for the Battle of France. One way to look at the Manstein Plan was that it was the German response to the French Dyle Plan. Originally, in Aufmarschanweisung N°1, Fall Gelb (Campaign Instruction No 1, Case Yellow), the Germans planned to push the Allied forces back through central Belgium to the Somme river, in northern France, similar to the 1914 campaign of the First World War.
On 10 January 1940, the Mechelen Incident occurred, when a German aircraft carrying documents containing parts of the operational plans of Fall Gelb crashed in Belgium, thus prompting another review of the invasion plan. While Fall Gelb was revised by Halder, not fundamentally changing it in Aufmarschanweisung N°3, Fall Gelb, Manstein was able to convince Hitler in a meeting on 17 February, that the Wehrmacht strategy should be an attack through the Ardennes, followed by an advance to the coast.
