Undines

The human-elemental marriage motif Paracelsus attached to undines was already an old and well developed literary tradition by his own time. Jean d'Arras's Roman de Melusine, written in French around 1393, gave the fullest and most influential medieval telling of a water-spirit who marries a human nobleman on condition he never see her on a particular day, a condition he eventually breaks, precipitating her transformation and departure; the House of Lusignan in France claimed actual descent from Melusine, treating the legend as real family history rather than mere folklore. Paracelsus, writing more than a century later, drew on this already substantial body of Melusine-type stories circulating across French, German and other European folk traditions rather than inventing the marriage motif himself, and simply gave the general type a place within his own systematic four-element scheme of elemental beings.

The Golden Dawn later assigned undines their own ruling king, Nichsa, within the fourfold system it built on top of Paracelsus's original scheme, a name, like the kings assigned to the other three elements, without any documented source earlier than the Order's own late nineteenth-century ceremonial material.

Paracelsus made one remark about water spirits that outran everything else he wrote on the subject. Lacking souls of their own, he said, they could acquire one by marrying a man, and the marriage bound the man in turn. He offered it as a piece of natural philosophy. It became the plot of a whole century of European art.

Friedrich de la Motte Fouque's novella Undine, published in 1811, is the point at which the remark turned into a story. A water maiden marries a knight, gains a soul and with it the capacity to suffer, and is betrayed. The book was an immediate and lasting success across German Romanticism and it fixed the shape that every later version would use.

What followed is a small industry. E. T. A. Hoffmann set it as an opera, Albert Lortzing set it again, and Tchaikovsky wrote an Undina he later destroyed most of. Jean Giraudoux's play Ondine reached the Paris stage in 1939 and has been revived steadily since. Hans Christian Andersen's Little Mermaid belongs to the same family of stories about a water being who trades her element for a soul and a man, and loses both.

The strangest survival is medical. Congenital central hypoventilation syndrome, in which the automatic control of breathing during sleep fails, was for many years called Ondine's curse, after the version of the tale in which the betrayed water spirit condemns her husband to keep breathing only so long as he remembers to. Clinicians have largely dropped the name, but it is still met in older literature, and it is an unusually direct route from a sixteenth century marginal note to a diagnostic term.