The decline of France's guarantor power began with its invasion of the Spanish Netherlands, legally a part of the Empire, in 1667. A turning point was the invasion of the Dutch Republic in 1672. Louis XIV declared that, since the Republic lay outside the Empire, any assistance given to such an enemy of France by the Empire or its members was a violation of the Peace of Westphalia and of the guarantee. Thereafter, France was no longer perceived as the protector of German liberties. The beginning of the Eternal Diet, the perpetual session of the imperial diet after 1663, hastened the decline of France's standing in the Empire, since the diet provided an internal mechanism for settling disputes.