The Gebroeders de Jong’s Leen Foundation was presented to civil-law notary mr L.K. van Giffen in St. Anna Parochie on September 2, 1921 by Mr. Tj. de Jong was founded and has its registered office in Leeuwarden. The statutory objective of the foundation is to allow descendants of Herre Rinia and Reinskje van der Sluis, spouses who have lived in Cornwerd near Makkum, to study from the income of the foundation.