The Acte van Consulentschap (Dutch pronunciation: [kɔn.syˈlɛnt sxɑp] ; in English historiography variously known as Act of Advisership, or less correctly, as Act of Consultation) was a secret, private contract between stadtholder William V, Prince of Orange of the Dutch Republic and his mentor and former guardian Duke Louis Ernest of Brunswick-Lüneburg, concluded on 3 May 1766 (shortly after William's majority), in which the latter was informally given continued powers of guardianship over the stadtholder in his private and public capacity. When the document became public in 1784, it caused such a scandal that the stadtholder's regime was almost fatally undermined in the political upheaval of the Patriottentijd.