According to tradition, the first temple on the banks of the Rumney River in Llanedeyrn was founded in the sixth century by Saint Edeyrn. In the twelfth century, the Normans erected a new church, which they made a chapel of ease subject to the church of St. Mary in Cardiff. In the 12th century it was declared the property of the Tewkesbury Abbey, but was returned to the Llandaff bishops in 1236, when it became a separate parish. At the turn of the fifteenth and sixteenth century, the church was rebuilt, among others, new windows in the perpendicular gothic style and a tower were added. The Victorian restoration of the building was carried out in 1888.
The church consists of a rectangular nave and a slightly lower, rectangular chancel on the eastern side. The western side is ended by a 15th / 16th century tower, lightly embedded in the nave. It has an entrance portal on the west side and is topped with a parapet and battlement. On the north side, it has a small projection in the wall that holds the staircase. An even shallower projection in the wall is located on the north side of the nave, where once there was a staircase to the rood loft. The southern entrance to the nave is preceded by a porch. The currently walled, priest portal was located in the southern wall of the chancel.
Website britishlistedbuildings.co.uk, Church of St Edeyrn. A Grade II Listed Building in Old St. Mellons (Hen Laneirwg), Cardiff.