Trewen is a hamlet in E Cornwall, 5 miles W of Launceston and E of Bodmin Moor, in the valley of the River Inny, a tributary of the Tamar. The church has a nave and chancel in one with a single bell cote over the W gable, A S porch and a N aisle with its own W gable. It is built of stone rubble with an ashlar N aisle, and is largely 15thc. It was restored by J. P. St Aubyn in 1863-64. The only Romanesque feature is the font.

Trewen was held by Eadwig in the time of Edward the Confessor and by Berner from the Count of Mortain in 1087. It was a daughter or chapel of South Petherwin, which belonged, with Trewen to St Germans Priory.

The plain font is made of local polyphant stone,an igneous serpentinite which is very hard and coarse grained. It can be polished, but this font is not, although a description of the conservation work undertaken in 1863 reveals that it was previously coated with whitewash, removed at the restoration (Royal Cornwall Gazette). The same article gives the architect as Mr C. P. Wise of Launceston and the contractor as Mr Squires of Broadwood.