What is the origin of the idea that Michael is Jesus?

I recently came across the idea of identifying the angel Michael as Jesus. I'm surprised I hadn't heard it before. Wikipedia documents it as common to Seventh Day Adventists and Jehovah's Witnesses. I'm not interested in biblical support of this theory; there are several other questions in that vein with good answers. I'd like to know more of its origin. Sub-questions to help guide what I'd consider a good answer: - How old is this idea? Wikipedia says "early Protestants", but cites John A. Lees (1939) who in turn cites Ernst Wilhelm Hengstenberg (1849) who doesn't appear to have a source beyond himself. They are far too recent to be "early Protestants". - Who (or what group) came up with the idea? - If it started with the adventists , how did it spread to Jehovah's Witnesses? - Do any orthodox forks* of Christianity accept the idea? - Do any orthodox forks* of Christianity explicitly reject the idea? (I'm surprised not to see it mentioned in the Catholic Encyclopedia.) \* **fork**: picture the christian religion as a road. Way back, promoters of Arianism were a fork in the road that dead ended fairly quick. The Protestants led many forks in the road. Mormons are yet another fork in the road. EDIT: Re: "early protestants". I just found a reference by John Calvin in his Commentaries on Daniel vol. 2, pg 243 . > Some think the word Michael represents Christ, and I do not object to > this opinion. [...] But as this is not generally admitted, I leave it > in doubt for the present [...] and there's a bit more in chapter 12 , but so far I haven't found who he is referencing by "some". Calvin does go on to defend associating Michael with Christ.