French operations in Artois , Champagne and Alsace from November–December 1914 , led General Joseph Joffre , Generalissimo ( Commander in Chief ) and head of Grand Quartier Général ( GQG ) , to continue the offensive in Champagne against the German southern rail supply route and to plan an offensive in Artois , against the lines supplying the German armies from the north .

Belfort is located in a gap between the mountainous southern Vosges and the Jura Massif , strategically positioned Placing as the gateway between Alsace and central France .

The Austrian victory in the First Battle of Wissembourg threatened Warning to overrun the territory of Alsace .

The Second Battle of Wissembourg on 25–26 December would decide Deciding the fate of Alsace .

The war began Process_start with separate insurrections , beginning Process_start in the southwestern part of what is now Germany and Alsace , and spread Dispersal in subsequent insurrections to the central and eastern areas of Germany and present-day Austria .