The Dukes of Brandenburg were rulers of the historical region of Brandenburg in present-day Germany. They emerged in the 12th century and played a significant role in the development of the Margraviate of Brandenburg, which later became part of the Holy Roman Empire. The dukes were influential in expanding their territory and consolidating power. In 1415, the title of Duke of Brandenburg was elevated to Elector, granting the holder a vote in the election of the Holy Roman Emperor. The House of Hohenzollern became the most notable dynasty among the dukes, eventually leading to the establishment of the Kingdom of Prussia and the unification of Germany in the 19th century.