Rudolf I was a Habsburg ruler and the first Habsburg elected as Holy Roman Emperor, laying the foundation for the Habsburg Monarchy's future dominance.
Frederick William I was a Prussian King known for his military prowess, economic reforms, and the creation of the famous Potsdam Giants regiment.
Frederick William III was the King of Prussia from 1797 to 1840, leading the nation through the tumultuous Napoleonic Wars and initiating significant administrative and social reforms.