Question: Where was the builder of Walferdange Castle a Prince of?

full_context: Document 1: Royal palace of Werla: The Royal Palace of Werla (German: "Königspfalz Werla") is located near Werlaburgdorf (municipality: Schladen-Werla) in Lower Saxony. The grounds of the royal palace cover about 20 hectares rising atop Kreuzberg hill, a 17 m high natural plateau overlooking the Oker river. In the Early Middle Ages the palace was an important place in the Holy Roman Empire, serving as an important base for the Ottonians in the 10th century in particular. Although it subsequently lost its political significance to the newly established Imperial Palace of Goslar at Rammelsberg, it developed into an independent settlement with a busy industrial quarter. In the 14th century it fell into ruin and was completely unknown until its rediscovery in the 18th century. The core fortress in particular was thoroughly excavated in the 20th century. Excavations carried out since 2007 have brought new understanding to the hitherto largely unexplored outworks. Since 2010 the palace complex with foundation and enceinte, as well as earthworks, has been partially reconstructed and is now open to the public as the "Archäologie- und Landschaftspark Kaiserpfalz Werla" (Archaeological and Wilderness Park of the Imperial Palace of Werla).
Document 2: Frederick Henry, Prince of Orange: Frederick Henry, or Frederik Hendrik in Dutch (29 January 1584 – 14 March 1647), was the sovereign Prince of Orange and stadtholder of Holland, Zeeland, Utrecht, Guelders, and Overijssel from 1625 to 1647.
Document 3: Walferdange Castle: Walferdange Castle (French: "Château de Walferdange" ), located in the small town of Walferdange in central Luxembourg, dates from 1824 when William I of the Netherlands who was also Grand Duke of Luxembourg built it as a stud farm. It is now part of the University of Luxembourg.
Document 4: William II, Prince of Orange: William II (27 May 1626 – 6 November 1650) was sovereign Prince of Orange and stadtholder of the United Provinces of the Netherlands from 14 March 1647 until his death three years later. His only child, William III, reigned as King of England, Ireland, and Scotland.
Document 5: William III of England: William III (Dutch: "Willem" ; 4 November 1650 – 8 March 1702), also widely known as William of Orange, was sovereign Prince of Orange from birth, Stadtholder of Holland, Zeeland, Utrecht, Gelderland, and Overijssel in the Dutch Republic from 1672, and King of England, Ireland, and Scotland from 1689 until his death. It is a coincidence that his regnal number (III) was the same for both Orange and England. As King of Scotland, he is known as William II. He is sometimes informally known in Northern Ireland and Scotland as "King Billy".
Document 6: Het Oude Loo: Het Oude Loo (] ; The Old Woods) is a 15th-century castle on the estate of Het Loo Palace in Apeldoorn in the Netherlands. The castle was built as a hunting lodge and is surrounded by a moat. The castle is currently used by the Dutch Royal Family as a country house and guest residence. It is not open for the public.
Document 7: Prince Frederick of Orange-Nassau: Frederick, Prince of Orange-Nassau (English: William George Frederick , Dutch: "Willem George Frederik" ; 15 February 1774 6 January 1799) was the youngest son of William V, Prince of Orange and Stadtholder of the Dutch Republic and Princess Wilhelmina of Prussia, sister of King Frederick William II. Commonly called Fritz inside the family, he chose a military career with the Holy Roman Empire, he died of a fever while serving in Padua, Italy.
Document 8: Fort Wilhelmus: Fort Wilhelmus was a factorij in the 17th-century colonial province of New Netherland, located on what had been named Hooghe Eyland (High Island) (also called Verhulsten Island) on the Zuyd Rivier, now Burlington Island in the Delaware River in New Jersey.
Document 9: Oranienstein Letters: The Oranienstein Letters are a series of letters sent by William V, Prince of Orange in December 1801 from Schloss Oranienstein near Diez, Germany. William addressed them to 15 Orangist ex-regenten of the old Dutch Republic, whom he advised to no longer stay out of government. This meant that some of his instructions given in the Kew Letters, that urged resistance against the French–Batavian invasion, were no longer in effect. He and his son, William Frederick, also recognised the Batavian Republic as legitimate, and renounced their hereditary stadtholderate. These were preconditions set by First Consul Napoleon of the French Republic for compensation for the loss of their possessions in the Netherlands, that had been confiscated by the Batavian Republic.
Document 10: William I, German Emperor: William I, or in German Wilhelm I (full name: "William Frederick Louis of Hohenzollern", German: "Wilhelm Friedrich Ludwig von Hohenzollern" , 22 March 1797 – 9 March 1888), of the House of Hohenzollern was King of Prussia from 2 January 1861 and the first German Emperor from 1 January 1871 to his death, the first Head of State of a united Germany. Under the leadership of William and his Minister President Otto von Bismarck, Prussia achieved the unification of Germany and the establishment of the German Empire. Despite his long support of Otto von Bismarck as Minister President, William held strong reservations about some of Bismarck's more reactionary policies, including his anti-Catholicism and tough handling of subordinates. Contrary to the domineering Bismarck, William was described as polite, gentlemanly and, while a staunch conservative, more open to certain classical liberal ideas than his grandson Wilhelm II.
Document 11: Waleran, Duke of Lower Lorraine: Waleran II (or Walram II) ( 1085 – 1139), called "Paganus" meaning "the Pagan", probably due to a late baptism, was the Duke of Limburg and Count of Arlon () from his father's death in about 1119 until his own twenty years later. He was given the Duchy of Lower Lorraine by Lothair of Supplinburg in 1128 after the latter's accession as King of Germany in 1125.
Document 12: Vredenburg Castle: Vredenburg Castle (Dutch: "(Kasteel) Vredenburg" or "Vredeborch") was a 16th-century castle built by Habsburg emperor Charles V in the city of Utrecht in the Netherlands. Some remains of the castle, which stood for only 50 years, are still visible on what is now Vredenburg square in Utrecht.
Document 13: William I of the Netherlands: William I (Willem Frederik, Prince of Orange-Nassau; 24 August 1772 – 12 December 1843) was a Prince of Orange and the first King of the Netherlands and Grand Duke of Luxembourg.
Document 14: Luxembourg City: Luxembourg (Luxembourgish: "Lëtzebuerg" , French: "Luxembourg" , German: "Luxemburg" ), also known as Luxembourg City (Luxembourgish: "Stad Lëtzebuerg" or "d'Stad ", French: "Ville de Luxembourg" , German: "Stadt Luxemburg" ) , is the capital city of the Grand Duchy of Luxembourg (also named "Luxembourg"), and the country's most populous commune. Standing at the confluence of the Alzette and Pétrusse rivers in southern Luxembourg, the city lies at the heart of Western Europe, situated 213 km by road from Brussels, 372 km from Paris, and 209 km from Cologne. The city contains Luxembourg Castle, established by the Franks in the Early Middle Ages, around which a settlement developed.
Document 15: William, Duke of Nassau: Wilhelm (Given names: "Georg Wilhelm August Heinrich Belgicus") (14 June 1792, Kirchheimbolanden – 20 August/30 August 1839, Bad Kissingen) was joint sovereign Duke of Nassau, along with his cousin Frederick Augustus, reigning from 1816 until 1839. He was also sovereign Prince of Nassau-Weilburg from 1816 until its incorporation into the duchy of Nassau.
ground_truth: Orange