In European folklore of the medieval and early modern periods, familiars were believed to be supernatural entities, interdimensional beings, or spiritual guardians that would protect or assist witches
A late-16th-century English illustration of a witch feeding her familiars
A story of "a priest who for the space of 40 years employed a familiar spirit", illustrated in Elizabeth I of England's copy of the Histoires Prodigieuses by Pierre Boaistuau
Prince Rupert and his "familiar" dog in a pamphlet titled "The Cruel Practices of Prince Rupert" (1643)
The Love Potion by Evelyn De Morgan, 1903: a witch with a black cat familiar at her feet
Boy was a white hunting poodle belonging to Royalist commander Prince Rupert of the Rhine during the English Civil War. Parliamentarian propaganda alleged that the dog was "endowed" with magical power
Familiar
…as animals, only in Greece During the English Civil War, the Royalist general Prince Rupert was in the habit of taking his large poodle dog named Boy into battle with him. Throughout the war the dog was greatly feared among the Parliamentarian forces and credited with supernatural powers. As noted…
In Royalist parodies, Boy was said to be a 'Lapland Lady' who had been transformed into a white dog.
Pro-Parliamentary pamphlet of 1643
A contemporary depiction of Boy's death