Another time also, while the blessed man was living in the Iouan island (Hy, now lona), he made this known to the assembled brethren with very great earnestness, saying, “To-day I wish to go alone to the western plain of this island; let none of you therefore follow me.” They obeyed, and he went alone, as he desired. But a brother, who was cunning, and of a prying disposition, proceeded by another road, and secretly placed himself on the summit of a certain little hill which overlooked the plain, because he was very anxious to learn the blessed man’s motive for going out alone. While the spy on the top of the hill was looking upon him as he stood on a mound in the plain, with arms extended upwards, and eyes raised to heaven in prayer, then, strange to tell, behold a wonderful scene presented itself, which that brother, as I think not without the leave of God, witnessed with his own eyes from his place on the neighbouring hill, that the saint’s name and the reverence due to him might afterwards, even against his wishes, be more widely diffused among the people, through the vision thus vouchsafed. For holy angels, the citizens of the heavenly country, clad in white robes and flying with wonderful speed, began to stand around the saint whilst he prayed; and after a short converse with the blessed man, that heavenly host, as if feeling itself detected, flew speedily back again to the highest heavens. The blessed man himself also, after his meeting with the angels, returned to the monastery, and calling the brethren together a second time, asked, with no little chiding and reproof, which of them was guilty of violating his command. When all were declaring they did not know at all of the matter, the brother, conscious of his inexcusable transgression, and no longer able to conceal his guilt, fell on his knees before the saint in the midst of the assembled brethren, and humbly craved forgiveness. The saint, taking him aside, commanded him under heavy threats, as he knelt, never, during the life of the blessed man, to disclose to any person even the least part of the secret regarding the angels’ visit. It was, therefore, after the saint’s departure from the body that the brother related that manifestation of the heavenly host, and solemnly attested its truth. Whence, even to this day, the place where the angels assembled is called by a name that beareth witness to the event that took place in it; this may be said to be in Latin “Colliculus Angelorum” and is in Scotic Cnoc Angel (now called Sithean Mor). Hence, therefore, we must notice, and even carefully inquire, into the fact how great and of what kind these sweet visits of angels to this blessed man were, which took place mostly during the winter nights, when he was in watching and prayer in lonely places while others slept. These were no doubt very numerous, and could in no way come to the knowledge of other men. Though some of these which happened by night or by day might perhaps be discovered by one means or another, these must have been very few compared with the angelic visions, which, of course, could be known by nobody. The same observation applies in the same way to other bright apparitions hitherto investigated by few, which shall be afterwards described.
— Vita Columbæ, Lib. iii. cap. xvii.