Loth, King of the Picts, had a beautiful daughter named Thernin, who loved and was loved by Eugenius I, King of the Scots, but, more fair than wise, she found herself one day about to become a mother, though she was not a wife.
When Loth was made aware of his daughter's condition, in anger and grief he ordered her to be dashed to her death from the rock on Mount Dunpeld before she should have disgraced him as well as herself.
She fell from the height, but fell unhurt; then Loth sent her away to Culross, where she gave birth to a son.
When St Servan, one morning, was in his cell saying Matins, he heard angel voices singing, and following whither they led came to the edge of the sea, where in the half light of dawn he found the young mother rocking her child and weeping. Filled with compassion, the old monk took the girl and the child to his cell, and there kept them, and did for them all that a father would have done.
He baptized the boy Kentigern, but what he called him was Mungo, which means 'Dearest.' And truly he loved him as his own son; so well that other lads whom he had under his tutelage were jealous of his partiality. They therefore hated Kentigern, and did all that occurred to them to grieve and annoy him.
It was in those days difficult to make fire unless one had a flame to start it with; it was, indeed, next to impossible. So it was the duty of each of the boys in turn to rise in the night and mend the fire lest it should go out before morning. Once, when it was Kentigern's turn to tend it, the boys put it out, to bring him into disgrace. When Kentigern arose in the morning and the fire was quite dead, he allowed himself not a moment's dismay; he held a stick over the dead ashes, called upon the aid of the Holy Trinity, blew upon the wood, and it leaped into flame.
On another occasion, the boys did a thing more detestable. There was a robin redbreast which was the special pet of St Servan, who used to feed it out of his hand, let it perch on his shoulders, and watch it delightedly as it sang and fluttered its wings while he chanted the Psalms.
The boys wrung this robin's neck, intending to accuse Kentigern of the murder. When he found the dead bird tears streamed from his eyes, not only tears of grief for the robin, but grief for his beloved benefactor. Picking up the pathetic remains in his hand, he made a prayer to God and a Sign of the Cross over the little stiff body, and the robin, reviving, flew off to meet St Servan on his return from Mass.
At last, unable longer to endure the miseries inflicted on him by his tormentors, Kentigern ran away. St Servan followed and found him. He remonstrated and pleaded with him to return, but Kentigern had heard the voice of God calling him elsewhere, so in the end, with St Servan's blessing, he went his way.
He settled near Glasgow in a cave in the face of a rock. In course of years he became Bishop of Glasgow, and there spent the greater part of his days, though he was for one period in Wales, where he built the monastery of Llan Elwyn.
In Glasgow he lived under the reign of a good King, Roderick the Liberal, who was his devoted friend.
The wife of Roderick, so the story goes, being so foolish and unfortunate as to contract a reprehensible passion for a knight of her husband's court, was further so unwise as to give him in pledge of her affection a ring which had been bestowed upon her by the King.
One day, as the King and this knight were out hunting they spent the hot hours of noon resting in the shade of some trees on the bank of the river Clyde. The air was heavy, the chase had been keen, both were exhausted, and the knight, overcome with weariness, slept. In his sleep he stretched out his hand in full view of the King, who, when his eyes fell upon the ring which had been a token of his own love for the Queen, with difficulty refrained from smiting the knight dead. Subduing his wrath, he reached out and, taking the ring from the unconscious hand, flung it into the stream at his feet.
On his return, going directly to the Queen, he asked her for the ring. When she was unable to show it, he ordered her to be cast into a dungeon and there put to death. With difficulty the Queen obtained a respite of three days' time. Then, having sent to the knight imploring him to return the ring, and having learned that it was gone from his finger, she sent in despair to St Kentigern, entreating him to come to her aid. She told him all her story, and he, remembering his own mother to whose shame he himself owed his being, and wishing to save the Queen for repentance and the service of God, fervently prayed with her, and for her.
That night a salmon caught in the Clyde was sent the Bishop. Upon opening it he discovered the ring. He sent the fish with its precious contents to the Queen. She showed the ring to the King and her life was saved.