In 1793, the French soldiers captured in the Siege of Mainz were paroled by the Prussians with the promise not to fight against the First Coalition for one year.

They were paroled by the Prussian army on condition that they not fight against the First Coalition for one year.

Army of the Rhine commander Alexandre de Beauharnais pointed out that the terms did not exclude them from fighting against French rebels inside France.

Therefore, 14,000 troops from the garrison were sent to the War in the Vendée under Jean-Baptiste Annibal Aubert du Bayet where they proved to be better soldiers than the poorly-trained armies fighting there.

The superiority of the Mainz corps was so evident that it provoked jealousy and in November 1793 the force was broken up.