I found no English Michaels in my tree - but a couple of Irish Michaels married in. That's how it might have got more popular in the C20th.
Still, I mentioned earlier in the thread that I had (amongst others) no Peters in my tree, but this is probably because mine didn't use it because it wasn't in their family, and they were conservative about names for most of the C19th. Other people's trees have generations of Peters, though it wasn't common - likewise I find Kezias and Thirzas amongst neighbours, but not in mine.
As I think I wrote before, if a name has given rise to a *surname* then it must have been common at the time surnames were formed - so Mitchell indicates descent from a Michael, Perkins from Peter. Perhaps Michael was seen as a Catholic name and fell from grace amongst Protestants.
Finally, when I come across a name like "Headache" my first thought is "mistranscription". I found a "Silly" - I know girls were named after virtues, and the saying "Be good, sweet maid, and let who will be clever" implies hte dangers of education, it turned out to be "Sibly" by someone who couldn't spell "Sybil".
Chris