Plan XVII
Plan XVII (pronounced [plɑ̃ dis.sɛt]) was the name of a "scheme of mobilization and concentration" that was adopted by the French Conseil Supérieur de la Guerre (the peacetime title of the French Grand Quartier Général) from 1912 to 1914, to be put into effect by the French Army in a war between France and Germany. It was a plan for the mobilisation, concentration and deployment of the French armies, to make possible an invasion of either Germany or Belgium or both, before Germany completed the mobilisation of its reserves simultaneous with a Russian offensive.[1]
For the German plan, see Schlieffen Plan.Plan XVII
Strategic
1912–1914
Joseph Joffre and the Conseil Supérieur de la Guerre
Joseph Joffre
Decisive defeat of Imperial German Army
7 August 1914
French Army
Failure
329,000
The plan was implemented from 7 August 1914, with disastrous consequences for the French, who were defeated in the Battle of the Frontiers (7 August – 13 September) at a cost of 329,000 casualties. The French armies (and the British Expeditionary Force) in Belgium and northern France were forced into a retreat as far as the Marne river, where at the First Battle of the Marne (5–12 September), the German armies were defeated and forced to retreat to the Aisne river, eventually leading to the Race to the Sea.
Background[edit]
Concentration plans 1871–1911[edit]
After the French defeat in the Franco-Prussian War 1870–1871, from 1874–1880, General Raymond Adolphe Séré de Rivières (20 May 1815 – 16 February 1895) oversaw the construction of the Séré de Rivières system, a line of fortresses 65 km (40 mi) long from Belfort to Épinal and another line of similar length from Toul to Verdun, about 40 km (25 mi) back from the frontier. The River Meuse flows northwards from Toul to Verdun, Mézières and Givet on the Belgian border and a tributary of the Moselle between Belfort and Épinal, near parallel to the 1871–1919 French-German border. The Trouée de Charmes (Charmes Gap), 70 km (43 mi) wide, between Épinal and Toul was left unfortified and the fortress city of Nancy was to the east, 12 km (7.5 mi) from the German frontier. A second series of fortifications, to prevent the main line being outflanked, was built in the south, from Langres to Dijon and in the north from La Fère to Rheims and from Valenciennes to Maubeuge, although for financial reasons these defences were incomplete in 1914.[2]
During the 1870s, the French army drew up concentration plans according to a defensive strategy, which exploited the Meuse and branches of the Moselle parallel to the 1871 border. The completion of the fortress lines between Belfort and Verdun in the late 1880s and railway building from the interior to the border, then gave the French army the means to contemplate a defensive-offensive strategy, in which a German attack would be repulsed and then followed up by a counter-attack. In August 1891, Plan XI was completed, with an option for an offensive as well as a defensive strategy from the start, to exploit the opportunity created by the improvement in relations between the Third Republic and the Russian Empire. The Franco-Russian Alliance (1892–1917) led to Plan XII in February 1892, in which an immediate invasion of Germany was considered possible. But from Plan XI to Plan XVI, the strategy remained defensive-offensive, French attacks being expected after the repulse of a German invasion.[2]
In 1888, the French began to study a possible German offensive north of Verdun or through Belgium and Plan XII was written with a contingency for a German breach of Belgian neutrality. In 1904, this was given more attention after a German (Le vengeur [The Avenger]) sold a copy of the German concentration plan to French intelligence and described mobilisation methods and war plans. Using this windfall and other sources of information, the French adapted Plan XV of 1906, to be ready for a German invasion of Belgium and later plans contained increases in the forces to be assembled to the north and north-east of Verdun. Plan XVI of March 1909, anticipated a German enveloping manoeuvre through Luxembourg and Belgium, after the findings of a 1908 analysis by General Henri de Lacroix, in which he dwelt on the German preference for enveloping manoeuvres and predicted that two German armies would march through eastern Belgium, around the northern flank of the French fortress zone, one to emerge from the Ardennes at Verdun and the other at Sedan. Lacroix wanted to improve the prospects of the usual defensive-offensive strategy by assembling a new Sixth Army near Châlons-sur-Marne, (now Châlons-en-Champagne), 80 km (50 mi) west of Verdun, easily to move towards Toul in the centre, Verdun on the left or to the vicinity of Sedan and Mézières behind the northern flank.[3]
Books
Journals
Theses