Early 70's Horror with Seance and Ghostly Knight

by Helen
(Canada)

I am trying to find the title of a horror movie which I saw in the early 70's, possibly 72 or 73. I have been searching for the title for some time. it is not " The Devil Rides Out" All I remember is, it was in a spooky house (mansion), there was a seance and at midnight strange things would happen. A ghostly knight appeared. I also remember that they had to stay in a circle salt for protection.

Please Help!!!