Charles I, Duke of Brunswick-Wolfenbüttel (1 August 1713 – 26 March 1780) married Princess Philippine Charlotte of Prussia and had issue. Anthony Ulrich of Brunswick-Wolfenbüttel (28 August 1714 – 4 May 1774 (O.S.)) married Grand Duchess Anna Leopoldovna of Russia and had issue.
Son of Charles William Ferdinand. During the Napoleonic Wars, from 1806 to 1813, France occupied Brunswick-Wolfenbüttel. Died in battle at Quatre Bras. Frederick William's son Charles (a minor at the time of his father's death) became the first Duke of independent Brunswick. Duchy of Brunswick