Frederick William III, Elector (Brandenburg) and King (Prussia), from 1806 only King of Prussia (Kingdom of Prussia (Territories outside the HRE)) : All Data

Frederick William III was the Elector of Brandenburg and later the King of Prussia from 1797 until his death in 1840. He ruled during a tumultuous period in European history, including the Napoleonic Wars (1803-1815) and the War of the Sixth Coalition (1812-1814). Despite facing significant challenges, Frederick William III managed to maintain Prussia's independence and territorial integrity. He famously resisted Napoleon's attempts to incorporate Prussia into his empire and played a crucial role in the formation of the Sixth Coalition, which ultimately led to Napoleon's defeat. Frederick William III's reign was marked by his efforts to modernize Prussia and strengthen its military, laying the foundation for the future unification of Germany.