Bernhard Erasmus von Deroy (1743-1812)

Bernhard Erasmus von Deroy was born at Mannheim into a military family in the Electoral Palatinate. Entering service at a young age, he served as a cadet during the Seven Years’ War. He advanced through the Palatine officer corps and, by the opening of the Revolutionary era, held senior rank; in 1792 he became Generalmajor. During the War of the First Coalition he served as commandant of the fortress of Mannheim and directed its defence in 1794–1795 against French forces; contemporary Bavarian accounts treated the earlier capitulation of the place as not attributable to his actions.

In 1800 he commanded a Bavarian corps in British pay during the renewed coalition fighting in southern Germany. During the campaign culminating in Hohenlinden (3 December 1800), he fell into French captivity. After his return, he was appointed (1801) to the Bavarian commission charged with improving the army. In 1804 he worked with Karl Philipp von Wrede on new Bavarian service regulations; within the division of reform labour in Munich, Deroy was associated particularly with the reorganization, training, and internal ordering of the infantry.

In the War of the Third Coalition (1805), he commanded Bavarian troops operating under French strategic direction; Bavarian formations were employed in securing and holding lines of communication and in operations connected with the Tyrol after the Austrian incursion into Bavaria had been reversed. He received field command of the 1st Bavarian Division in 1806. During the 1806–1807 campaign, Bavarian forces served in the north-eastern theatre alongside French armies; Deroy’s division participated in siege operations in Silesia, including the reduction of Brieg and decisive participation in the assault on Glatz.

In 1809, during the War of the Fifth Coalition, Deroy’s division was employed in the Tyrolean theatre amid recurring insurgent warfare. In the fighting around Innsbruck and the Bergisel actions, Bavarian control of the province proved unstable; Deroy conducted withdrawals into Bavaria and subsequently took part in renewed coalition-directed efforts to re-establish authority when additional Bavarian and French forces became available. He was promoted General der Infanterie in 1811.

In 1812 Deroy again commanded the 1st Bavarian Division in the Russian campaign as part of the Bavarian contingent serving with the Grande Armée in the northern sector. He was mortally wounded near Polotsk in August 1812 and died there on 23 August. He held the Grand Cross of the Bavarian Military Order of Max Joseph and high grade in the French Légion d’honneur, and he was created a French Graf in 1812.

Sources

• Deutsche Biographie: Deroy, Bernhard Erasmus von (französischer Graf 27.8.1812)
• Bayerische Staatsbibliothek (MDZ): Leben des Grafen Bernhard Erasmus v. Deroy, k.b. Generals der Infanterie
• Bayerische Staatsbibliothek (MDZ): Erinnerungen an den General der Infanterie Erasmus Graf v. Deroy
• Historisches Lexikon Bayerns: Tiroler Aufstand (1809)
• Wikipedia (English): Bernhard Erasmus von Deroy