Attached to the Museum de Gevangenpoort is the Galerij de Prins Willim V. Throughout his life Prince William of Orange amassed an impressive collection of art. In 1774 he opened his private gallery to the public to be the first public art gallery. The collections is primarily pieces from Dutch and Flemish painters from the Dutch Golden age, such as Steen, Potter, van Mieris, van Honthorst and Rubens. Although the actually gallery is long gone, his collection remains and is on display in a similar style to the original gallery. In addition to this specific gallery, pieces from Prince Willem V’s collection comprise the basis for many museums throughout Holland.