There are several stories in particular that frame the majority of Irish folklore regarding werewolves. In Northern Ireland it is said that there were tribes of wolf-men living in the wild that ancient Kings would call on to aid them in battle. Other tales claim that creatures, half wolf, half man, wander the forests, sometimes preying on cattle and sheep, other times protecting the people. And an even older myth tells the tale of three werewolf women yearly emerging from a cave to slaughter sheep during a Harvest Feast, and who were finally lured with music and massacred.
The most well known legend of werewolves in Ireland, however, was recorded by Giraldus Cambrensis, also known as Gerald of Wales, a clergyman and royal clerk to the British King in the 1100s, assigned the task of observing and recording political and socio-economical events. In his work exploring Ireland, Topographia Hibernica, he depicts the Irish as being savage and primitive with repugnant orthodox piety. He does, however, do us one justice: he records a tale of two werewolves of Ossory, which a priest had personally encountered, and Giraldus was requested to give counsel.
As a side note, the wolf was the totem of Ossory, and for good reason. It is said that long ago, Ossorians had the power to change into a werewolf at will. Once changed, the werewolf’s human body would remain lifeless at home until the wolf could return to it and thus resume his human form. It is also said that if you were to harm the wolf form, corresponding wounds would be found on the human form; thus you could always tell if a man was indeed a werewolf.
Yet, interestingly enough, Giraldus’ record was not of this Ossarian legend, but of another: a curse had been lain on a family to which they, although Christians, were condemned to wander as savage wolves for seven years. In his record, a werewolf was pleading with a traveling priest to come and perform the rite of viaticum on his dying wife, who was also in wolf form. The priest concedes and goes on to tell his experience to the local bishops who call Giraldus for counsel. Giraldus is unable to make the appointment but sends a letter instead. Eventually, the werewolf tale reaches even the Pope, who gives his seal on the account.
There is also an intriguing Irish folklore that Natalis, a monk living in the early 5th century, cursed a prominent family for unknown reasons. The curse? Each member of the family was doomed to become a wolf for seven years.
As far as my research can tell, there is a fascinating correlation between these two historical references to werewolves that has yet to be investigated. Is Giraldus’ account of the Ossarian werewolf couple somehow related to the original curse imprecated by Natalis, nearly 600 years earlier?
In any case, the legend of the Ossarian werewolves has deeply founded roots, including a historical account by the Royal Clerk. Yet when and how the werewolves came to be is still a matter of folklore. You’ll have to sort it out for yourselves.