Grand Duchy of Luxembourg is a landlocked country in western Europe, bordered by Belgium, France, and Germany. Luxembourg has a population of over half a million people in an area of approximately 2,586 square kilometres (999 sq mi). Luxembourg is a parliamentary representative democracy with a constitutional monarch; it is ruled by a Grand Duke. It is the world's only remaining sovereign Grand Duchy. Its historic and strategic importance dates back to its founding as a Roman era fortress site and Frankish count's castle site in the Early Middle Ages. It was an important bastion along the Spanish Road when Spain was the principal European power influencing the whole western hemisphere and beyond in the 16th–17th centuries.