Belfort Gap

It is also the boundary between the historic regions of Burgundy to the west and Alsace to the east, and as such has marked the Franco-German border for long periods of its history.

The Belfort Gap is first recorded as playing a military role in 58 BC, when Julius Caesar marched his army through it to confront the Germanic chieftain Ariovistus, whom he defeated at the Battle of the Vosges probably fought in the vicinity of modern Mulhouse.

In the early 6th century, both Burgundy and Alemannia were conquered by the Kingdom of Francia, but the Belfort Gap remained the linguistic border between Germanic and Romance languages.

The Belfort Gap acquired renewed significance in the series of Franco-German wars in the nineteenth and early twentieth centuries.

At the outbreak of the First World War, French troops invaded Germany through the Belfort Gap, leading to the bloody Battles of the Frontiers.

View south from Offemont , across the Belfort Gap toward the Jura .
The Belfort Gap (in the southwest) and the other regions of Alsace.
The Belfort Gap is visible in the bottom centre of this map of the 1944 campaign.