Morris dancing is not documented prior to about 1450. The reference shows that it was an established practice by then in the place where the reference occurs, but the lack of earlier documentation suggests that it was a recent innovation. In prior centuries we hear of dances like the carole and the estampie. Some have suggested that the morris is a continuation of a dance that was earlier known under another name, but I don't know on the basis of what evidence. I remain skeptical.
References to "the" old religion falsely presuppose that it was a single, unified phenomenon. It is better to imagine a complex religious situation of diverse, and to some extend competing, priesthoods, secret societies, shrines, temples, local customs, festivals, and of course charlatans too.