As to their dwellings, the Fairies were "things under the earth," for they were generally supposed to dwell in the lower regions, especially beneath lakes, where their country towns and castles were situated; and the people on the coasts of Pembrokeshire imagined that they inhabited certain enchanted green isles of the sea.
The green meadows of the sea, called in the old Welsh Triads Gwerddonau Llion, are the:
"Green fairy islands, reposing, In sunlight and beauty on ocean's calm breast."
A British King in ancient times, whose name was Garvan is said to have sailed away in search of these islands, and never returned. Garvan's voyage is commemorated in the Triads as one of the "Three Losses by Disappearance." Southey after citing Dr. W. O. Pughe's article in the "Cambrian Biography," goes on as follows:--
"Of these Islands, or Green Spots of the Floods, there are some singular superstitions. They are the abode of the Tylwyth Teg, or the fair family, the souls of the virtuous Druids, who not having been Christians, cannot enter the Christian Heaven, but enjoy this heaven of their own. They, however, discover a love of mischief, neither becoming happy spirits, nor consistent with their original character; for they love to visit the earth, and seizing a man, inquire whether he will travel above wind, mid-wind, or below wind; above wind is a giddy and terrible passage, below wind is through bush and brake, the middle is a safe course. But the spell of security is, to catch hold of the grass. In their better moods they come over and carry the Welsh in their boats. He who visits these islands imagines on his return that he has been absent only a few hours, when, in truth, whole centuries have past away. If you take a turf from St. David's Churchyard, and stand upon it on the sea shore, you behold these Islands. A man once who thus obtained sight of them, immediately put to sea to find them; but his search was in vain. He returned, looked at them again from the enchanted turf, again set sail, and failed again. The third time he took the turf into his vessel, and stood upon it till he reached them." Wirt Sikes, in his "British Goblins," page 8, says that there are sailors on the romantic coasts of Pembrokeshire, and southern Carmarthenshire who still talk of the green meadows of enchantment, which are visible sometimes to the eyes of mortals, but only for a brief space, and they suddenly vanish. He also adds that there are traditions of sailors who, in the early part of the 19th century, actually went ashore on the fairy islands--not knowing that they were such, until they returned to their boats, when they were filled with awe at seeing the islands disappear from their sight, neither sinking in the sea, nor floating away upon the waters, but simply vanishing suddenly. In the account I have just given, a turf from St. David's Churchyard to stand upon enabled one to behold the enchanted lands of the Fairies; but according to traditions in other parts of the country, it seems that a certain spot in Cemmes was the requisite platform, to see these mythical beings who were known in some parts as Plant Rhys Ddwfn (Children of Rhys the Deep).