Prince William Maurice of Nassau-Siegen (18/28 January 1649 – 23 January 1691Jul.), , official titles: Fürst zu Nassau, Graf zu Katzenelnbogen, Vianden, Diez, Limburg und Bronkhorst, Herr zu Beilstein, Stirum, Wisch, Borculo, Lichtenvoorde und Wildenborch, Erbbannerherr des Herzogtums Geldern und der Grafschaft Zutphen, was a count from the House of Nassau-Siegen, a cadet branch of the Ottonian Line of the House of Nassau. He served as an officer in the Dutch States Army. In 1664, he was elevated to the rank and title of prince. In 1679 he became Fürst of Nassau-Siegen, a part of the County of Nassau. Biography William Maurice was born at in Terborg on 18/28 January 1649 as the eldest son of Count Henry of Nassau-Siegen and Countess Mary Magdalene of Limburg-Stirum. After the death of their father, William Maurice and his brother Frederick Henry were adopted by their uncle Fürst John Maurice of Nassau-Siegen. After the death of his maternal grandfather, Count George Ernest of Limburg-Stirum, in September 1661, William Maurice succeeded him as count of Bronkhorst, lord of , , and , and hereditary knight banneret of the Duchy of Guelders and the County of Zutphen. Thus, these properties came into the possession of the House of Nassau. On 29 April 1663, William Maurice became a hopman of a company of Swiss soldiers in the Dutch States Army. On 20 April 1672 he became lieutenant colonel of an infantry regiment and in 1673 he was promoted to colonel. In 1678 he also became ritmeester of a cavalry company to the repartition of Friesland. William Maurice and his brother Frederick Henry accompanied their uncle and adoptive father John Maurice on his journey to the city of Siegen, where they arrived on 21/31 August 1663. On 7 January 1664, the two brothers were inaugurated in the town hall of Siegen, where they confirmed the city privileges and liberties. Both brothers were elevated into the Reichsfürstenstand on 6 May 1664. In 1667 William Maurice became a knight of the Order of Saint John (Bailiwick of Brandenburg, Saxony, Pomerania and Wendland) in Sonnenburg and commander of Grüneberg, and also a knight of the Teutonic Order (Bailiwick of Utrecht) and commander of Tiel. In October 1672, William Maurice came to the aid of his uncle John Maurice to defend Muiden in the Franco-Dutch War, with a company of soldiers ‘geworben in dem deutschen Stammlanden des Fürsten’, i.e. recruited in