A section of medieval arch is built into the exterior S wall of the S porch. Various works on the church are attested during the 19thc, the most important being a major remodelling and restoration undertaken in 1893, when the S porch was added. It is generally held that this section of arch was taken from the original chancel arch of the twelfth-century church, but no documentary evidence to substantiate this claim is known to exist. The base level and certain sections of walling of much of the nave appear also to date from the original church. The parish of Lundie was joined with that of Fowlis-Easter in 1618, though the teinds for the parsonage and vicarage of Lundie had already been annexed to the prebends of Fowlis-Easter Collegiate Church sometime between 1522 and 1538. Lady Duncan was responsible for the erection of a mausoleum off the east end of the church, which was built in memory of her husband, Sir William Duncan, in 1787-9. Before this was added, the old chancel arch was still visible, as seen in a print of 1786 (see: MacGibbon and Ross).

There are certain discrepancies in the coursing of the exterior nave walls, which suggest changes. The first of these involves the early base course, which does not extend as far as the present E wall of the nave. The end stone of the early base course on the N side of the nave appears to turn inward, which would suggest a corner at this point. The ashlar stones above, and to the west of this corner stone do not course with the stonework east of this. The second anomaly concerns the narrow nave window on the N exterior. The coursing of stone around it does not match the stonework either side of it.

The sawtooth arch, which is not of an early form, along with the surviving documentation appear to suggest a date no earlier than the 2nd half of the 12thc for the oldest parts of the church.