Son of Ferdinand Albert II (d. 1735) and Antoinette Amalie, dau of Louis Rudolph, Duke of Brunswick-Lüneburg. Brother of Karl I. A military man, he became commander of the allied Hanoverian army (which included the British forces) during the seven years war (1756-1763), before retiring in 1766. He led the allied army to victory against a superior French force at the Battle of Minden in 1759.1
Boswell was received at the Court of Brunswick on June 27, 1764. In his journal he described how "I sat opposite to Prince Ferdinand, whose presence inspires animated respect. He absolutely electrified me. Every time that I looked at him, I felt a noble shock."
Despite having dined opposite him on June 27, Boswell wasn't actually introduced to the Prince until the next day, when he was received in the Prince's bedchamber. They talked a good deal, and Boswell described the Prince as “a distinguished hero [who] had a force and yet an affability of address. He seemed a man of strong judgment and clear ideas."