 Despite the importance of the Anglican Church in the lives of the parishioners the growing strength of Nonconformity would make itself felt in the 18th century . In 1738 the Reverend Henry Davies formed the Independent Cause in Cymmer and five years later a ‘ ' Ty Cwrdd ’ ’ or meeting house was opened there . Although attracting families from as far away as Merthyr and the parish of Eglwysilan , there were no other Nonconformist Causes until David Williams began preaching in the Rhondda in 1784 . In 1785 six people were baptised in the river near Melin @-@ yr @-@ Om and in 1786 ‘ ' Ynysfach ’ ’ was opened in Ystrad and was “ a new house for religious services ” . This was the first Baptist chapel in the Rhondda and later became known as Nebo , Ystrad Rhondda . Cymmer and Ynysfach chapel would be the forerunners in a new religious movement in the valley for the next 150 years . In the early 19th century there were only three places of worship in the Rhondda ; the parish church ( now dedicated to St. John the Baptist ) , Cymmer and Ynysfach chapels . This changed rapidly after 1855 as the coal mining industry brought in an influx of population and by 1905 there were 151 chapels in the valley . 
