By a similar treaty he promised subsidies and the province of Alsace to the Duke of Saxe-Weimar.

He entered into an arrangement with the Dutch, who were to aid France to conquer Flanders, which was to be divided between the two powers; while the Dukes of Savoy, Parma, and Mantua agreed to undertake, in alliance with France, the invasion of Milan, and to receive in return a portion of the territory won from Spain.

At the same time France declared war against Spain.

It was to the army commanded by Cardinal de la Valette, which was to act with that of Saxe-Weimar against the Imperialists, that Turenne was attached.
The campaign began unfavourably.

The impetuosity of Saxe-Weimar, who hoped to recover his own principality, induced Valette to cross the Rhine; but he was forced to retire in all haste, and the army suffered terribly in the retreat.