 The Rhondda also has the remains of two Medieval castles. The older is Castell Nos which is located at the head of the Rhondda Fach overlooking Maerdy. The only recorded evidence of Castle Nos is a mention by John Leland who stated that "Castelle Nose is but a high stony creg in the top of an hille". The castle comprises a scarp and ditch forming a raised platform and on the north face is a ruined drystone building. Due to its location and form it does not appear to be of Norman design and is therefore thought to have been built by the Welsh as a border defence; and must therefore date before 1247 when Richard de Clare seized Glynrhondda. The second castle is Ynysygrug, located close to what is now Tonypandy town centre. Little remains of this motte-and-bailey earthwork defence as much was destroyed when Tonypandy railway station was built in the 19th century. Ynysygrug is dated around the 12th century or early 13th century and has been misidentified by several historians, notably Owen Morgan in his book 'History of Pontypridd and Rhondda Valleys' who recorded it as a druidic sacred mound and Iolo Morgannwg who erroneously believed it to be the burial mound of king Rhys ap Tewdwr.
