 Complete the following phrase:  By the French Revolutionary Wars at the end of the 18th century, the use of body armour had declined to virtual extinction. Of all principal European armies, it was only the Austrian one that continued to employ armoured cuirassiers en masse. However, except when confronting the Ottomans like during the war of 1788-1791, only a breastplate was worn. The Austrian reform of 1798 even increased the number of cuirassier regiments by three, although the state of the cuirass itself was not altered, not abandoning it, but also not readding the backplate of old. This would eventually proof fatal during the battle of Eckmühl in 1809, when the French cuirassiers with their full cuirasses decisively defeated the Austrian cuirassiers. Indeed, Napoleonic France would eventually put much emphasis on armoured cavalry, although the former Cuirassiers du Roi regiment, known after the revolution as Cavalerie-Cuirassiers, would continue to be the sole French regiment using body armour until the reforms of 18021803. By the order of king Frederick William II, Prussian cuirassiers were discarding their armour. This was the case first for a few regiments participating in the 