League of the Rhine

The League of the Rhine (also known as the Erster Rheinbund, First Rhine-Bund; or the Rheinische Allianz - Rhenish Alliance) was a defensive union of more than 50 German princes and their cities along the River Rhine, formed on 14 August 1658 by Louis XIV of France and negotiated by Cardinal Mazarin (the de facto prime minister of France), Hugues de Lionne and Johann Philipp von Schönborn (Elector of Mainz and Archchancellor of the Empire).

Its intended aim was to weaken the position of the Holy Roman Emperor, Leopold I and to marginalise the Austrian House of Habsburg.

Louis XIV had wished to be elected emperor himself, but had failed, despite the French victory at the Battle of the Dunes.

The League's members also swore to maintain the clauses of the 1648 Treaty of Westphalia, which had made the League possible by authorising the German princes, immediate vassals of the Emperor, to conclude alliances between themselves or with foreign states.

It officially ended in August 1667, but its end should in fact be dated to 1668 since French diplomacy succeeded in negotiating a further extension of the alliance as the Rheinbundrat, made up only of the main members of the League, which lasted to 1688.