Monastic Origin
Once known as the South Chapel, built near a holy well on the banks of the Camel. St Michael’s is one of the two ancient chapelries included in the parish of St Minver. The other is St Enodoc, or the North Chapel. There is some reason to suppose that St Michael’s began as an oratory for a monastic order, housed in the neighbouring farm where traces of ecclesiastical architecture are still visible. The parish of St Minver was from 1255 in the gift of the Prior of Bodmin, and it is said that the two farmhouses at the gate were the house of Labour and the House of Rest of Bodmin Priory. By 1284 these two farms, Porthilly Eglos and Porthilly Grey, has already been for some time in lay hands and still are.
Norman Church.
The Normans originally built St Michael’s and we can still see traces of the 12th century building. This consisted of a nave, chancel and south transept. The south transept was evidently widened westward by the 13th century builders who placed a lancet window in the east wall and a piscina to serve the little chapel. In the 15th century the south wall of the chancel was removed and a still smaller chapel or south chancel aisle was added, less the 5 ½ feet wide. An archway was made in the south wall of the transept to give access to the newly built chapel.
Screen and Pulpit
It was probably the same builders who erected the chancel screen of which the lower part remains. The pulpit may have been made from the upper part of the screen. Access to the top of the original screen was made from a newal staircase built in the north wall of the chancel, the door to the staircase being built in the chancel instead of on the nave side, the usual way of approach. Part of the staircase still exists.
There are still some interesting pieces of old window tracery of early and late 13th century on the south side of the church where a memorial window has been engraved by David Pearce M.B.E, R.I.B.A. There is another piscina of the 14th century in the south wall. A very unusual feature of the church is the inclination of the north wall to the south-a reminder of how Jesus head hung on the cross.
Rounseuall Memorial.
Behind the font can be found a large slate plaque attached to the wall and carved with the inscription
"Here lyeth the body of William Rounseuall who was buried the 25th December anno Dom. 1659. Jane his wife was Buried ye 4th of Aug’s’t 1679."
Cross
Outside the door is a fine granite cross. It was removed to the present position from the west end of the chapel. In heraldry it is called a "cross degraded", that is, the ends are fixed in a step, or degree, and are united by a rim or oriole, and the panels within the arms are pierced. These holed crosses are comparatively rare and are probably of the 5th to 8th centuries. Their original purpose was to mark preaching stations or the boundary of the property or as guides to church. The Rev. William Henry, a previous Vicar , thought Porthilly was on the original Pilgrim Way from Ireland via Cornwall to Rome.