High Quality Content by WIKIPEDIA articles! Ysgyryd Fawr is the most easterly of the Black Mountains in Wales, part of the Brecon Beacons National Park. The name is often anglicised to The Skirrid or Skirrid Fawr, and the mountain is also known as Holy Mountain or Sacred Hill. The spelling Skyrrid is also encountered in older literature. The lower hill of Ysgyryd Fach or `Little Skirrid` (270m) lies about 4.5 km / 2.5 mi to the south.