This castle (16C-17C), known as Poptaslot or Heringastate, is one of only a few fortified manor houses which has survived in Friesland. Built around 1500 and owned by the Heringa family, it was sold in 1687 to the rich and influential lawyer Dr Henricus Popta from Leeuwarden. He furnished the house and made it his summer residence, founding a hospice (Popta-Gasthuis) nearby. He requested that the house should be conserved in its original state after his death and remain uninhabited for 300 years.