The site of Penrhys has a rich religious history dating back to medieval times, though few settlements other than farmsteads can be traced to the area.

[3][4] In the medieval period the area became an important pilgrimage centre, known for Ffynnon Fair (English: Mary's Well), a holy well that still exists.

Although a 'fever hospital' had been constructed in nearby Ystrad, the threat of smallpox had become a concern to the Medical Officer of Health, who recommended a separate containment site.

In 1906 the Health Committee purchased three acres of land at Penrhys, chosen for its accessibility to both Rhondda valleys and its distance from other habitable buildings.

The march was organised by the South Wales Miners' Federation and the Rhondda District, but lost support due to opposition from the TUC.

Built between 1966 and 1969 by Alex Robertson, Peter Francis & Partners, the houses consisted of short two and three storey terraces with cement rendered concrete walls and monopitch roofs.

The outflow of employed residents led to a process of social engineering (whether intentional or not) whereby those on unemployment or other state benefits were relocated into Penrhys from other council-run estates, with the initial prospect of saving on separate heating costs.

In an attempt to rejuvenate the village, the Priority Estate Programme was undertaken in the late 1980s with all houses refurbished and environmental improvements made throughout the community.

This, though, proved unsuccessful as the reputation of Penrhys was so low that new occupants could not be found; this led to newly refurbished houses being vandalised as they stood empty.

It was originally believed that the monastery was Franciscan and built under the orders of Henry I; another tale states that Welsh king Rhys ap Tewdwr was beheaded by the Normans at the site.

The original statue survived at Penrhys until 1538[10] when, under Henry VIII's dissolution of the monasteries, Bishop Latimer wrote to Thomas Cromwell suggesting the destruction of the shrine.

[11] In the early 20th century Miss M. M. Davies of Llantrisant, a Catholic convert, supplied funds for the construction of a memorial church to be built at nearby Ferndale.

Gibbons, parish priest of the church at Ferndale revived the pilgrimages and in 1939 the Rhondda Borough Council, recognising the importance of the site, took measures to restore and protect the Holy Well.

Standing on a plinth and although much larger than the original, was carved from Portland stone using the descriptions left behind in medieval Welsh poetry.

[12] Due to its religious importance, Penrhys is part of the Cistercian Way, and many people still make pious pilgrimages to the site every year.