Ferns Castle | Heritage IrelandBefore the coming of the Normans, Ferns was the political base of Diarmait Mac Murchada, king of Leinster. William, Earl Marshall built the castle aroundBefore the coming of the Normans, Ferns was the political base of Diarmait Mac Murchada, king of Leinster. William, Earl Marshall built the castle around 1200. Since then it has had many owners, of diverse political and military colours. Originally, the https://heritageireland.ie/visit/places-to-visit/ferns-castle/