The original chapel in the place of the later church in Rhos on Sea, was erected in the 13th century. It was built by Ednyfed Fycha, the seneschal of the Welsh kingdom of Gwynedd, and was first mentioned in the documents in 1254. In the fifteenth and the sixteenth century century it was rebuilt and enlarged into the form of the present church. In 1552, a tower was added. Further modifications were introduced in the 17th centuries, and a thorough Victorian renovation was carried out in the 19th century. The church was erected on a hill and whitewashed, to serve as a landmark for sailors at sea. Probably because of the proximity of the sea on the tower, a smaller observation turret was added, to alert the local population in the event of pirate attack, being the plague of the seventeenth century.
The church from the fifteenth century consisted of a rectangular nave with no externally separated chancel. In the sixteenth century, the southern nave was built with an equal length and the same shape as the previous one and a four-sided tower on the western side. The porches were added both to the southern and northern nave.
Website britishlistedbuildings.co.uk, Church of St Trillo A Grade II Listed Building in Rhos-on-Sea, Conwy.
Website historypoints.org, St Trillo’s Church, Llandrillo-yn-Edeyrn.