Frederick William, Duke of Brunswick-Wolfenbüttel (1771-1815)

Frederick William was a German prince and soldier of the House of Welf, known in contemporary and later usage as the Schwarzer Herzog (“Black Duke”). After the collapse of his duchy under Napoleonic occupation, he raised the volunteer corps commonly called the Black Brunswickers and later led Brunswick forces in Coalition service through the Waterloo Campaign, where he was killed at Quatre Bras.

Born at Wolfenbüttel on 9 October 1771, Frederick William entered Prussian service as a youth (1787). He progressed through regimental duty during the Revolutionary era and was present with Prussian forces in the opening campaigns against France, including the 1792 operations that culminated at Valmy. Through the 1790s he remained in Prussian uniform, building a professional identity primarily as an army officer rather than a court figure.

In 1805 he inherited the Silesian principality of Oels, which broadened his dynastic responsibilities. The following year brought catastrophe. His father, Duke Charles William Ferdinand, was mortally wounded during the 1806 campaign; Frederick William succeeded to the Brunswick inheritance in the same period, only to see the territory seized and incorporated into Napoleonic client rule (notably the Kingdom of Westphalia). In the Prussian debacle of 1806, he served under Blücher during the retreat to the north; the capitulation and ensuing fighting around Lübeck led to his capture in early November 1806.

With his lands lost and his position reduced to exile and opposition, Frederick William re-entered the field during the War of the Fifth Coalition. In 1809 he formed a Freikorps (about 2,000 men in some contemporary accounting), distinguished by black uniforms and the death’s-head emblem. From May 1809 the corps operated in central and northern Germany; it fought a series of actions during its advance and withdrawal, including the storming of Halberstadt (29 July 1809) and the engagement at Ölper near Brunswick (1 August 1809). Cut off from stable Coalition support after the armistice, he led his force to the North Sea and evacuated to Britain in August 1809.

In British service, elements of his corps were organized and employed as Brunswick-Oels Jäger and hussar formations. These Brunswick troops campaigned in the Peninsula and are recorded in a sequence of Major engagements, including Fuentes de Oñoro, Salamanca, Vitoria, the Pyrenees, Nivelle, the Nive, and Orthez. During this period Frederick William himself lived largely in exile, maintaining Brunswick’s cause and personnel under British auspices while Coalition fortunes shifted.

The Coalition advance of 1813 allowed Frederick William to return to Brunswick and re-establish a ducal government while rebuilding forces for the continuing war against Napoleon. In the Hundred Days crisis of 1815 he took the field in the Low Countries with a Brunswick contingent (commonly cited at roughly brigade-to-division strength) allied to Wellington’s army group. On 16 June 1815, at the Battle of Quatre Bras, he was killed while leading his troops. Brunswick units continued in the campaign and fought two days later at Waterloo.

Sources

• Deutsche Biographie: “Friedrich Wilhelm (1771–1815), Herzog von Braunschweig-Lüneburg”
• British Museum: “Frederick William, Duke of Brunswick-Lüneburg, Prince of Oels (1771–1815)”
• National Army Museum: “‘Duke of Brunswick-Oels’, 1815”
• Royal Collection Trust: “Duke of Brunswick-Oels (Frederick William…)”