[2] A pious woman, she settled at Rescobie near Forfar in Angus, but her beauty attracted the attentions of a King of the Picts named Nechtan.

According to the 13th-century Orkneyinga Saga, John prayed to "Trøllhaena", and later regained his sight when brought to her "resting place", possibly referring to a local northern shrine rather than Restalrig.

The exterior of the aisle was heavily restored by the architect Thomas Ross in 1907, though its interior (which has a remarkable echo) retains its original rib-vault, and is a refined example of Scottish 15th-century architecture.

Lamb (1983:19) notes: Immediately outside the W wall Traill broke into a subterranean passage which he followed N then NW for some 10m, passing several sets of door-checks and a side-chamber and entering a 'circular building'.

It is possible that that a broch lies at the core of the mound, on the lower SE slope of which a revetment-wall, 1.9m high and traceable for 11m, may be part of an outer wall or ringwork.

A cross-slab is said to have been seen some years ago in the deep water besides the islet, but an attempted recovery was unsuccessful.St Tredwell or Triduana is associated as a 'holy virgin' with St Boniface in a medieval account of the mission from Jarrow to Pictland in 710 invited by King Nechtan.

Marwick, in a paper written in 1925, cites John Brand in his Brief Description of Orkney (1700) as having much to say of the chapel: People used to come to it from other isles; before the chapel door was a heap of small stones, "into which the Superstituous People when they come, do cast a small stone or two for their offering, and some will cast in Money"; the loch is "held by the People as Medicinal"; "a Gentleman in the Countrey, who was much distressed with sore Eyes, went to this Loch and Washing there became sound and whole...with both which persons he who was Minister of the place for many years was well acquainted and told us that he saw them both before and after the Cure: The present minister of Westra told me that such as are able to walk use to go so many times about the Loch, as they think will perfect the cure before they make any use of the water, and that without speaking to any... not long since, he went to this Loch and found six so making their circuit..." "As for this Loch's appearing like Blood, before any disaster befal the Royal Family, as some do report, we could find no ground to believe any such thing.In the 19th century the Minister of Westray, John Armit, noted that: Such was the veneration entertained by the inhabitants for this ancient saint, that it was with difficulty that the first Presbyterian minister of the parish could restrain them, of a Sunday morning, from paying their devotions at this ruin, previous to their attendance on public worship in the reformed church.