Continuity mistake: When Samantha gets up off the couch to confront the wood nymph, the pillow on the couch, on the left side of the screen, is laying flat. When they move back in front of the couch when Endora arrives, the pillow is standing up against the armrest.
Continuity mistake: When Samantha goes back to the 15th century, Geri O'Toole is wearing a yellow dress. When Samantha pops back home, Darrin is wearing Thea Ames hit but Geri is wearing a pink dress. It all happened the same afternoon/evening. Geo should still be wearing the same yellow dress.
Factual error: Benjamin Franklin is portrayed as a gentleman in this episode and the previous My Friend Ben episode. In this episode he dates Aunt Clara at the end. In reality, Benjamin Franklin was a cad, a womanizer and a playboy. He was a marvellous man - a genius - but treated women terribly refusing to marry his common law wife, abandoning her for years while he played with other women in Europe... and treated his daughter like a second class citizen.