The House of Orange-Nassau (, ) is the current reigning house of the Netherlands. A branch of the European House of Nassau, the house has played a central role in the politics and government of the Netherlands and Europe especially since William the Silent organised the Dutch Revolt against Spanish rule, which after the Eighty Years' War (1568–1648) led to an independent Dutch state. Several members of the house served during this war and after as stadtholder ("governor"; Dutch: stadhouder) during the Dutch Republic. However, in 1815, after a long period as a republic, the Netherlands became a monarchy under the House of Orange-Nassau. The dynasty was established as a result of the marriage of Henry III of Nassau-Breda from Germany and Claudia of Châlon-Orange from French Burgundy in 1515. Their son René of Chalon inherited in 1530 the independent and sovereign Principality of Orange from his mother's brother, Philibert of Châlon. As the first Nassau to be the Prince of Orange, René could have used "Orange-Nassau" as his new family name. However, his uncle, in his will, had stipulated that René should continue the use of the name Châlon-Orange. After René's death in 1544, his cousin William of Nassau-Dillenburg inherited all of his lands. This "William I of Orange", in English better known as William the Silent, became the founder of the House of Orange-Nassau. Origins Nassau Castle was founded around 1100 by Dudo, Count of Laurenburg, the founder of the House of Nassau. In 1120, Dudo's sons and successors, Counts Rupert I and Arnold I, established themselves at Nassau Castle, taking for themselves the title "Count of Nassau". In 1255 the Nassau possessions were split between Walram and Otto, the sons of Count Henry II. The descendants of Walram were known as the Walram Line, and they became Dukes of Nassau and, in 1890, Grand Dukes of Luxembourg. This line also included Adolph of Nassau, who was elected King of the Romans in 1292. The descendants of Otto became known as the Ottonian Line, and they inherited parts of the County of Nassau, as well as properties in France and the Netherlands. The House of Orange-Nassau stems from the younger Ottonian Line. The first of this line to establish himself in the Netherlands was John I, Count of Nassau-Siegen, who married Margaret of the Mark. The real founder of the Nassau fortunes in the Netherlands was John's son,