Partrishow

It is in the valley of the Grwyne Fawr, in the Black Mountains of South Wales, within the Brecon Beacons National Park.

The eariest recorded form of the name, as found in the Book of Llandaf (c.1120s), is merthir issiu.

[2] In this case, the element llan ('enclosure, church') has replaced merthyr, as has happened in a number of similar names.

[3] The name appears as Pertrissw in the list of parishes in National Library of Wales, Peniarth MS.147 (c.1566).

The village is noted for its outstanding grade I listed 11th-century Church of St Issui[4][5][6] with an intricately carved 16th-century rood screen,[7] mediaeval mural paintings,[8] and one of the oldest fonts in Wales.