St. Guinefort, The Sorceress & The Dominican Inquisitor
A Dominican friar, Etienne de Bourbon, was sent as an inquisitor to Sandrans, a small village north of Lyon. He relates his findings in the work, De Supersticione. It was published in 1240 A.D.
One of the sections is called De Adoratione Guinefortis Canis, or, On the Worship of the Dog Guinefort. It relates the tale of the brave and loyal greyhound, Guinefort, or saves his master’s son from a snake who attempted to get into his crib. 
Guinefort defended the baby and tossed the snake across the room. The snake bit the dog, and there was blood all over the dog’s head and nursery floor. The mother and the wet nurse came in to find the bloody scene. They screamed, bringing the knight in with sword drawn, who killed the dog.
Finding the baby safe and sleeping peacefully, they looked around for an explanation for all the blood. They discovered the snake dead and torn to pieces.
Realizing what really happened, and what they had done, the knight and women were filled with remorse and inconsolable regret. The dog was buried in a well, and his grave covered high with stones. Trees were planted around the site in the manner of a sacred grove.
The manor was abandoned by the family and the estate became wild land.
“The local peasants,” relates de Bourbon’s account, “hearing of the dog’s conduct and of how it had been killed, although innocent, and for a deed which it might have expected praise, visited the place, honored the dog as a martyr, prayed to it..” when their children were sick or needed help.
Infuriated to find “St. Guinefort” was a dog, the friar preached against his veneration. “We had the dead dog disinterred, and the sacred wood cut down and burnt, along with the remains of the dog.”
The tragic story seems to end there, but the French film The Sorceress (Le Moine et la Sorciere, 1987), written by Boston College medievalist Pamela Berger and directed by Suzanne Schiffmann gives it a new twist. 
The premise of the movie is this: in a town near Lyons village people venerate Saint Guinefort, a greyhound who once saved a child from a deadly snake. When a Dominican friar repesenting the Church’s inquisition comes to town, he is outraged by what he sees as a mockery of the Christian institution of sainthood.
The friar destroys the grave of the holy dog and cuts down a tree nearby that the townsfolk believe to have healing powers. Later, however, he comes to regret his actions. As sort of a compromise with the villagers, the friar builds a chapel on the site of the sacred tree, and reinvents Saint Guinefort as a man-saint with a dog companion.
The shrine of Saint Guinefort continued to be visited for another 700 years, through the 1940s. Perhaps it still exists.
