The church in Llanfwrog was erected in the thirteenth or fourteenth century, unfortunately it is not possible to specify the date of its beginning. In the fifteenth century it was enlarged by the addition of an extra nave. A thorough renovation of the chancel and nave was carried out in the years 1869-1870, and the tower at the beginning of the 20th century.
The original church consisted of a rectangular nave and a non-externally separated chancel, constituting one whole and covered with one roof. It is not known whether the church already had a tower from the very beginning, it was probably added in the 14th century. In the fifteenth century, a southern nave of the same length and width as the northern one was erected. From the south-west side, at the entrance portal there is a modern porch, but it uses timber from an earlier building. All windows, unfortunately, have been rebuilt in the 19th century.
Website cpat.demon.co.uk, Church of St Mwrog, Llanfwrog.