All Hallows eve is by the Welsh called ‘Nos Calan Gauaf,’ meaning ‘the first night of winter;’ sometimes, ‘Nos Cyn Gauaf,’ the ‘night before winter.’ It is one of the ‘Teir Nos Ysprydnos,’ or ‘three nights for spirits,’ upon which ghosts walk, fairies are abroad, mysterious influences are in the air, strange sights are seen, and in short goblins of every sort are to be with special freedom encountered. They may be conjured to appear, by certain enchantments, and to give their visitors glimpses of the future, especially as regards the subject of marrying. On this night it is customary for the  young people, gathered in many a merry circle, to seek by tricks and charms of various sort to become acquainted with their future lovers and sweethearts. Not that it is always necessary to employ such aids, for on the Teir Nos Ysprydnos the phantoms of future companions have been known to appear unsummoned. There are many such stories as that of Thomas... Williams, the preacher, who slept in the hills on a Nos Ysprydnos, and although he used no charms nor tricks of any sort, he saw his future wife. As he was just about putting out his light, having jumped into bed, the door opened and the goblin mother of the young woman he subsequently married walked into the room, leading her daughter. ‘Here, Thomas,’ said she, ‘I am going, but I leave you Mary.’ And when he came down home out of the mountains he found that the old mother had died in her bed at the very moment he saw her goblin. To have done less than marry the girl, after that, would have been to insult the good old lady’s ghost, and cast reflections on the reputation of All Hallows eve.
WELSH FOLK-LORE, FAIRY MYTHOLOGY,
LEGENDS AND TRADITIONS. WIRT SIKES,page 281See