Thomas of Erceldoune — Thomas the Rhymer, or 'True Thomas' — was a real 13th-century laird of Earlston in the Scottish Borders, named in charters of the 1290s, who passed into legend as Scotland's great prophet. The story tells how he lay down to rest beneath the Eildon Tree on the slopes of the Eildon Hills near Melrose, and saw a lady of marvellous beauty ride by in green silk on a milk-white horse hung with silver bells. Taking her for the Queen of Heaven, Thomas greeted her; she told him she was the Queen of Elfland, and challenged him to kiss her, knowing it would put him in her power.
The story
She carried him off on her horse, and they rode through darkness and across a river of blood to her Otherworld kingdom, where Thomas dwelt for what seemed three days but was seven years. Warned not to speak a word to anyone there lest he never return, he was at last brought back to the mortal world and given a parting gift — an apple, or 'the tongue that can never lie'. From then on Thomas could not tell a falsehood, and the prophecies he uttered were believed throughout Scotland: the death of Alexander III, the Battle of Bannockburn, and the union of the crowns were all later credited to him.
The spot of his meeting is still marked by the Rhymer's Stone near Melrose, where the Eildon Tree is said to have stood, and tradition holds that Thomas never truly died — that one day, when a hart and a hind walked through the village of Earlston, he followed the Queen's summons back into the hills and was never seen again. His tale, preserved as a medieval romance and as Child Ballad 37, is among the most influential fairy-abduction stories in the British tradition.