The House of Nassau is a European aristocratic dynasty. The name originated with a lordship associated with Nassau Castle, which is located in what is now Nassau in Rhineland-Palatinate, Germany. With the fall of the Hohenstaufen dynasty in the first half of the 13th century, royal power within Franconia evaporated and the former stem duchy fragmented into separate independent states. Nassau emerged as one of those independent states as part of the Holy Roman Empire. The lords of Nassau were originally titled "Counts of Nassau", subject only to the Emperor, and then elevated to princely rank as "Princely Counts". Early on, the family divided into two main branches – the elder (Walramian) branch, which gave rise to the German king Adolf, and the younger (Ottonian) branch, which gave rise to the Princes of Orange and the monarchs of the Netherlands.