St. Keynes Well

"The Cornish well of St Keyne has the remarkable property of giving supremacy in marriage to whichever one of a couple shall first drink of its waters. The woman saint who founded it planted over it four symbolic trees, oak, ash, elm and withy, all four, it was said, growing from one stem. They blew down in 1703 and were replaced by others (M. and L. Quiller-Couch, Ancient Holy Wells of Cornwall, 1894)"

"Where fresh water runs, there runs spirit, and this is particularly so wherever water springs up from below the earth, for it comes from the realm of the earth goddess and bears her gifts. Properly every spring has its seasons of efficacy when its virtues are most generously displayed. In times before doctors, psychiatrists, marriage guidance officials, newspapers, horoscopes, drugs and artificial fertilisers, all their functions were exercised by the spirits of the local springs, who required no payment but respect and attention. Yet it is the custom, wherever use is still found for the spirits in water, to reward their benevolence with gifts of coins, rags and trinkets, for spirits is believed to agree with magpies, jackdaws and children in their taste for glittering objects.
Ancient science had much use for the spirit in water. The holy well in the crypts of many cathedrals and churches is the original pre-Christian shrine. It accommodates the spirit of the place and provides the earth and lunar element (water being under the influence of the moon) to balance the solar invocation of the edifice. A temple, as an image of the universe, must comprehend all in nature, and so all ancient sacred sites have wells, springs, underground streams or catacombs in their foundations. Placed elsewhere than by a natural location of spirit, a temple would lack the medium it was designed to manipulate."
(from John Mitchell "The Earth Spirit, its ways, shrines and mysteries", Avon, 1975)