Old Cogan seems to have belonged to Llandough monastery in the time of the Saints and the church could date back to this time.
The original church consisted of a chancel and nave. Herringbone masonry
survives well throughout the chancel, but only the north wall of the
nave still retains such work in it's eastern half. The chancel
walls on the south and east sides are only herringbone up to head
height, the gable un upper part being made of random rubble.
Within is a crude, rustic Romanesque arch which has no quoins or
pillars, but does have projecting imposts.
Paul Martin Remfry