Kakwkylla
Kakwkylla was a local saint venerated in Sweden and Germany under a wide range of names during the Late Middle Ages. She served as protector against rats and mice. Her cult probably originated as a misnomer for the Irish saint Columba, apparently combined with misappropriated traits of Gertrude of Nivelles. In Sweden, where Columba was not widely venerated nor Gertrude of Nivelles associated with rats, Kakwkylla appears to have played a more independent role.
Depictions, name and origins
Late medieval depictions of a female saint, typically equipped with a spindle and spinning, and with rats either on the thread, on the saint or in the surroundings, are known from the Swedish churches of Film, Forssa, Harg, Kaga, Njutånger as well as possibly Viksta, and Hattula in Finland. Some of these also have speech scrolls identifying the saint. Similar depictions are also known from Germany, including on an altarpiece in the monastery of Adelberg, Baden-Württemberg under the name Cutubilla. A woodcut from the middle of the 15th century in the Kupferstichkabinett in Berlin also depicts the saint, and may indeed be indicative of how depictions of her were spread to Sweden, using early printing techniques. A large number of variations of the saint's name are known. From Sweden, the forms Kakwkylla, Kacacila, Kakitkaina, Kolla, and Katakyla are known. From German sources, the names Cakukilla, Cutubilla, Kakukabilla, Kakukilla and Kukakille have been identified.In a German context, the saint may have originated due to being confused with Columba, an Irish abbot and missionary to Scotland, venerated as a saint. His name may have been locally interpreted as a female name, and variants known from the 14th century indicate that distortions similar to the known names of the Swedish-German saint existed. A medieval prayer to Columba against fire also shows similarities to one of the known prayers to Kakwkylla; the Kakwkylla prayer may be a distorted version of the prayer to Columba. Furthermore, Columba is known to have been referred to also as Colum Cille, Kolumkilla and Kolumbilla during the Middle Ages. On the other hand, no known myths or legends associate Columba with rats, although a legend tells that Columba made the snakes on Iona lose their venom, and he may therefore have been seen as a protector against vermin in general.
Because of the lack of direct links between Columba and protection against rats, another theory posits that the saint in Germany was a mix-up with Gertrude of Nivelles, a female saint who had an association with rats and was occasionally depicted with rats as an attribute. Possibly, a combination of the two misunderstandings created the saint: the name was taken from Columba while the legend and patronage from Gertrude of Nivelles.
From Germany the veneration of the saint most probably spread to Sweden. Just how the saint reached Sweden is unknown, though she was probably not known there before 1500. In Sweden, she seems to have been venerated as an independent saint in her own right. There is no medieval evidence that Columba was ever venerated in Sweden, and the known depictions of Gertrude of Nivelle typically depict her with another attribute; it's therefore unlikely that Kakwkylla was the result of a confusion with other saints.