Rouen preserves a famous local legend in which the seventh-century bishop Saint Romanus defeats a dragon or water monster called La Gargouille with the help of a condemned prisoner. The legend became tied to Rouen's civic and religious memory, but it is a legend about a monster, not evidence that architectural gargoyles everywhere descend from that event. The similarity of the names helped later storytelling join the Rouen dragon to the carved waterspout.

The architectural gargoyle is first of all a drainage device. Medieval masons channelled roof water through a projecting stone spout so that rain would fall away from masonry, mortar and foundations. The projection could be carved into a dragon, dog, lion, bird, demon or distorted human form without changing its practical job. This functional distinction matters: a grotesque may look equally monstrous, but if it does not conduct water it is not technically a gargoyle.

Gargoyles became especially conspicuous on Gothic churches and other large medieval buildings. Their shapes vary widely, and surviving examples mix fearsome animals with comic, hybrid and human forms. The sculpture belongs to the wider medieval taste for marginal creatures on corbels, capitals, manuscripts and rooflines. No single medieval text gives one universal meaning for these figures.

Protective or apotropaic interpretations are often proposed for frightening architectural sculpture, but the meanings of individual gargoyles are rarely documented. Some may have been warnings, jokes, caricatures or moral images; others may simply have allowed masons creative freedom around a necessary water channel. Bernard of Clairvaux's famous complaint about monstrous carvings in monasteries shows how striking such imagery could be, but it does not provide a single explanation for every gargoyle.

Arthurian literature does not give the gargoyle an independent medieval myth. Its Mythopouch connection is visual and historical: later artists, filmmakers and fantasy designers often imagine Camelot and other Arthurian strongholds in Gothic architectural forms that naturally include gargoyles and grotesques. The creature therefore belongs to the later visual language surrounding medieval Arthurian settings rather than to an original episode in the romances.

The idea that a gargoyle can leave its perch is much younger than the stones. Nineteenth-century Gothic Revival architects fill new buildings with medieval-looking beasts, and Eugène Viollet-le-Duc, the French restorer of Notre-Dame, creates the famous chimeras now mistaken for medieval originals. Horror writers, fantasy artists, and role-playing games turn the stone sentinel into a living creature that wakes at night. The modern gargoyle flies, fights, and broods above the city. The medieval one remains where the mason placed it.

At sunrise the gargoyle is only stone. At sunset its shadows lengthen across the roof. When rain strikes the tower, its hidden throat fills, its jaws open, and water leaps away from the wall. Below, travellers pull their cloaks tighter and hurry toward the gate. Above them, the carved beast keeps the only watch it has always kept: silent, patient, and ready to speak with the voice of falling rain.