The Prussian Royal Family was the ruling dynasty of the Kingdom of Prussia, which played a significant role in German and European history. The family belonged to the House of Hohenzollern and produced several notable monarchs, including Frederick the Great, who reigned from 1740 to 1786 and is known for his military successes and cultural contributions. The royal family was instrumental in the unification of Germany in the 19th century, leading to the establishment of the German Empire in 1871. The last king of Prussia was Wilhelm II, who abdicated in 1918 following Germany's defeat in World War I, marking the end of the monarchy in Germany.