Landgraves were noble titles historically used in parts of Europe, particularly in the Holy Roman Empire and some German territories. The term "landgrave" refers to a ruler or lord of a specific region, often overseeing a territory known as a landgraviate. These nobles held significant power and were responsible for local governance, justice, and military duties. The title of landgrave was often hereditary, passed down through noble families. One of the most notable landgraves was Landgrave Philip the Magnanimous of Hesse, who played a crucial role in the Protestant Reformation. Landgraves contributed to the political and social structures of their regions, influencing the development of local governance.