Question: The Union of Delft was the signed by the prince of which part of France?

Context paragraphs:
Johannes Basius: Johannes Basius (c. 1540, Leeuwarden – 11 September 1596, Delft) was born in Friesland, and studied at Leuven and afterwards in France, where he was made a doctor of law.  He became then an advocate in his native country and an agent and adviser of Prince William of Orange.  He wrote "Paradoxorum Disputationem Juris Civilis".  Basius died as secretary of the senate at Delft, in Holland.

French assistance to Nguyễn Ánh: French assistance to Nguyễn Ánh, the future Emperor of Vietnam and the founder of the Nguyễn Dynasty whose name was later changed to Gia Long), covered a period from 1777 to 1820.  From 1777, Mgr Pigneau de Behaine, of the Paris Foreign Missions Society, had taken to protecting the young Vietnamese prince who was fleeing from the offensive of the Tây Sơn.  Pigneau de Behaine went to France to obtain military aid, and secured a France-Vietnam alliance that was signed through the 1787 Treaty of Versailles between the king of France, Louis XVI, and Prince Nguyễn Ánh.  As the French regime was under considerable strain at the eve of the French Revolution, France was unable to follow through with the application of the treaty.  However, Mgr Pigneau de Behaine persisted in his efforts and, with the support of French individuals and traders, mounted a force of French soldiers and officers that would contribute to the modernization of the armies of Nguyễn Ánh, making possible his victory and his reconquest of all of Vietnam by 1802.  A few French officers would remain in Vietnam after the victory, becoming prominent mandarins.  The last of them left in 1824 following the enthronement of Minh Mạng, Gia Long's successor.  The terms of the 1787 Treaty of Alliance would still remain one of the justifications of French forces when they demanded the remittance of Đà Nẵng in 1847.

Prince Edward Islands Act, 1948: The Prince Edward Islands Act, 1948 (Act No. 43 of 1948) is an act of the Parliament of South Africa that annexed the Prince Edward Islands to the Union of South Africa (as it then was).  The South African flag was hoisted on Marion Island and Prince Edward Island on 29 December 1947 and 4 January 1948 respectively, and a proclamation of annexation was promulgated on 24 January 1948.  The annexation was confirmed by Parliament by the Prince Edward Islands Act, which was signed by the Governor-General on 1 October 1948 and came into force upon publication on 7 October.

Prince Robert, Duke of Chartres: Prince Robert Philippe Louis Eugène Ferdinand of Orléans, Duke of Chartres (November 9, 1840 – December 5, 1910) was the son of Prince Ferdinand Philippe, Duke of Orléans and thus grandson of King Louis-Philippe of France.  He fought for the Union in the American Civil War, and then for France in the 1870 Franco-Prussian War.  In 1863 he married his cousin Princess Françoise of Orléans in Kingston upon Thames – she was the daughter of François, Prince of Joinville.  In 1886, he was exiled from France.

Treaty of Orléans: The Treaty of Orléans was a marriage treaty signed in 1275, that led to a short-lived personal union between the kingdoms of Navarre and France.  It was signed by Philip III of France and his cousin Blanche of Artois, mother and regent to the two-year-old Joan I of Navarre.  The original intent of the treaty was not to create a personal union, however, but to enable Philip to administer Navarre in Joan's name.  Joan was also to marry either Philip's firstborn and heir apparent, Louis, or his second son, Philip.  Pope Gregory X explicitly stated that he preferred a match with the younger son, as he probably wished to avoid merging Navarre with France.  Louis died in 1276, however, leaving Philip as the only choice per the terms of the treaty.

Prince of Orange: Prince of Orange is a title originally associated with the sovereign Principality of Orange, in what is now southern France.  Under the Treaty of Utrecht of 1713, Frederick William I of Prussia ceded the Principality of Orange to King Louis XIV of France (while retaining the title as part of his dynastic titulature).  After William III of England died without children, a dispute arose between Johan Willem Friso and Frederick I of Prussia, which was settled in the Treaty of Partition (1732); consequently, Friso's son, William IV had to share use of the title "Prince of Orange" (which had accumulated prestige in the Netherlands and throughout the Protestant world) with Frederick William I of Prussia.  The title is traditionally borne by the heir apparent of the Dutch monarch.  The title descends via absolute primogeniture since 1983, meaning that its holder can be either Prince or Princess of Orange.

Union of Delft: The Act of Federation of 1576, (popularly known as the Union of Delft) was signed on 25 April 1576 by William the Silent (the then Prince of Orange) and the provinces of Holland and Zeeland in the Netherlands and made a definitive federation of the two provinces.  It also gave William supreme authority in war, allowed him to call a States General when he pleased, and effectively made him head of it.  This allowed him to better gather resources and plan for attacks on the invading Spanish.

Treaty of Paris (1814): The Treaty of Paris, signed on 30 May 1814, ended the war between France and the Sixth Coalition, part of the Napoleonic Wars, following an armistice signed on 23 April between Charles, Count of Artois, and the allies.  It established peace between France and the United Kingdom of Great Britain and Ireland, Russia, Austria, and Prussia, who in March had defined their common war aim in Chaumont.  The Treaty was also signed by Portugal and Sweden while Spain signed shortly after in July.  Peace talks had started on 9 May between Talleyrand, who negotiated with the allies of Chaumont on behalf of the exiled Bourbon king Louis XVIII of France.  The allies had agreed to reduce France to her 1792 borders and restore the independence of her neighbors after Napoleon Bonaparte's defeat.  However, the allied parties did not sign a common document, but instead concluded separate treaties with France allowing for specific amendments.

Treaty of Péronne (1641): The Treaty of Péronne was signed on September 14, 1641, in Péronne, France between Honoré II, Prince of Monaco, and Louis XIII, King of France.  Based on the terms of the treaty, Prince Honoré permitted Monaco to become a French protectorate in return for guarantees entailing the preservation of his rights as sovereign.  Moreover, Honoré wanted to be included in all French treaties and be given grants of land in France as compensation for any privately-owned territories he may lose in Habsburg Spain.  Overall, the treaty led to the removal of the Spanish garrison in Monaco by the French and ultimately regulated the relations between France and Monaco for 150 years.

Treaty of Paris (1810): The Treaty of Paris, signed on 6 January 1810, ended the war between France and Sweden after Sweden's defeat by Russia, an ally of France, in the Finnish War of 1808-1809.  Russia had previously been an ally of Sweden in the Third and Fourth Coalitions against France, but after Russia's defeat at Friedland, she joined France and attacked Sweden so as to compel her to join Napoleon's Continental System.  Indeed, the primary result of the treaty was Sweden's agreement to join the Continental System, so that Sweden would not trade with the UK.  Shortly after the treaty was signed, on 21 August 1810, one of Napoleon's marshals, Jean-Baptiste Bernadotte, was elected crown prince of Sweden, and he went on to found the House of Bernadotte, which remains the Royal House of Sweden.  The peace resulting from the treaty lasted until Napoleon's refusal to permit Sweden to annex Norway, which was then under the sovereignty of Denmark, an ally of France.  This was followed in January 1812 by French occupation of Swedish Pomerania for violation of the Continental System, since Sweden was still trading with the UK, and, in April, Sweden's conclusion of the Treaty of Petersburg with Russia against France.

Supporting paragraphs: Union of Delft Prince of Orange
Answer: southern France