...and from the History of Morris: "Three origin theories have been proffered:

It is derived from pre-Christian "fertility" dancers. A late 19th century theory based on a rationalization of the dance form (comparative studies of ritual and myth by the likes of Sir James Frazer and supported by Mary Neal, Cecil Sharp, and D'Arcy Ferris). (e.g. Handkerchief ward off evil, high jumps make crops grow, etc.).

It derives from Spain or the "Moors", hence Morisco or Moorish dancing. A theory dating to at least 1730 or earlier, but no evidence to support this, it seems to be just be a link in names.

It is from France or Flanders and was introduced during the reign of Edward III (1327-1377) or Henry V or VI, when many English lords and soldiers were in those countries. The first reference to this idea is in the mid 1800s.