THE HISTORY OF THE ANCIENT PARISH OF EGLWYSILAN                                                          

The Parish of Eglwysilan was one of the parishes created in Llandaff Diocese sometime in the 12th Century. This was done under the structuring of the Roman Catholic Church in those days when the country was divided into areas or diocese and subdivided into parishes. It covered an area of more than 30,000 acres which extended from Rumney to Abercynon, including both Caerphilly and Llanfabon. The Parish church of St Ilan was built on Mynydd Eglwysilan; ideally situated to serve such an extensive area because it commanded both the Taff and Aber Valleys . It is likely that this was built on the site of an earlier chapel or cell from the age of the saints.

During the 6th Century, St. Cenydd established a Monastery in Caerphilly, and possibly an ancient church at Senghenydd 'Capel Y Cenydd'. In their choices of routes and sites for outlying churches, St. Catwg (St. Cadog) and his disciples from Llancarfan made use of Roman roads. One of these monks, following the route to Gelligaer, possibly set up a cell at Eglwysilan.

The Parish reduced in geographical size over the centuries with the development of industry in the Taff and Rhymney Valleys and is now a Parish of some 8,000 people serving all of the Aber Valley and including the villages of Abertridwr and Senghenydd together with the hamlets of Eglwysilan and Goeswen.

This is a diverse Parish made up of a post mining valley and hill farming communities and residential areas (less than 10miles from the centre of Cardiff ). New housing is being constructed on the Windsor Colliery Site in Abertridwr. Senghenydd is the site of the Universal Colliery where the biggest mining disaster in History took place in 1913 claiming the lives of 440 in the 'Senghenydd Explosion'. This in turn had followed another terrible explosion in 1901 claiming the lives of 78. The disasters are remembered in the Valley with the Mining Museum and the memorial at the entrance to Nant y Parc primary School. 

In February 2015 the ancient Parish of Eglwysilan and the Parish of Caerphilly joined together to create the Rectorial Benefice of Eglwyisian and Caerphilly; continuing to serve the communities of the Aber Valley and Caerphilly.