The Norman church probably consisted of nave, chancel and S transept; together with the nave S wall and chancel S and E walls probably on the original foundations. Two Romanesque carved stones survive: a quarter capital and a base from a doorway shaft.

The Welsh saint Morwenna, the patron also of Morwenstowe, must have founded an oratory here prior to the Saxon conquest, which occurred earliest in this north-eastern area of Cornwall and more or less eliminated original Cornish place names. The manor of "Maronecircke" or "Maronacirca" mentioned in the Domesday Book was perhaps the Celtic endowment. This was of course secularized and Marhamchurch became an ordinary parish.

The motifs just discernible in the shields of the capital fragment resemble those used on one of the St. Teath capitals. Sedding suggests that the arches originally above the capital were square in section, probably with a recessed order as in Morwenstowe and St. Germans. In Henderson's time it was kept in the vestry, Dating: second quarter of 12thc. Sedding compared the base with those of the circular shafts of the S doorway of Holsworthy church in Devon. Dating: mid-12thc.