reading a novel the other day and one of the charactors patron saint was St. Guinefort - who was a dog. curiosity aroused - I checked on the web and found this:

" ...St. Guinefort. I thought he was some saint. I made inquiries and at last heard that he was a certain greyhound killed in the following way. In the diocese of Lyons, close to the vill of the nuns called Villeneuve, on the land belonging to the lord of Villars-en-Dombe, there was a certain castle whose lord had a baby son from his wife. But when the lord and lady and the nurse too had left the house, leaving the child alone in his cradle, a very large snake entered the house and made for the child's cradle. The greyhound, who had remained there, saw this, dashed swiftly under the cradle in pursuit, knocking it over, and attacked the snake with its fangs and answering bite with bite. In the end the dog killed it and threw it far away from the child's cradle which he left all bloodied as was his mouth and head, with the snake's blood, and stood there by the cradle all beaten about by the snake. When the nurse came back and saw this, she thought the child had been killed and eaten by the dog and so gave
out an almighty scream. The child's mother heard this, rushed in, saw and thought the same and she too screamed. Then the knight similarly once he got there believed the same, and drawing his sword killed the dog. Only then did they approach the child and find him unharmed, sleeping sweetly in fact. On further investigation, they discovered the snake torn up by the dog's bites and dead. Now that they had learned the truth of the matter, they were embarrassed (dolentes)that they had so unjustly killed a dog so useful to them and threw his body into a well in front of the castle gate, and placing over it a very large heap of stones they planted trees nearby as a memorial of the deed.

But the castle was in due course destroyed by divine will, and the land reduced to a desert abandoned by its inhabitants. The local peasants hearing of the dog's noble deed and innocent death, began to visit the place and honor the dog as a martyr in quest of help for their sicknesses and other needs. "

Stephen of Bourbon's exemplum On the worship of the dog Guinefort

elsewhere I found: "Despite the best efforts of the Inquisition to eradicate the cult of Saint Guinefort, people continued to visit the grove up to 1940, praying for the protection of their children. In 1987,.a movie was even made about the dog and his cult."