The history of the Reformation is a secular history by the definitions that we use (to the extent that “secular” can have a coherent definition, anyway). It is about the world that was changed dramatically in the 1500s, roughly.

If you teach it as the time when someone important to your tradition taught a doctrine your group agrees with, and transmitted it to you, you are really not teaching much of the Reformation.

The Reformation is when God broke down the medieval order so completely that it had to be replaced with a new order. Remaining Roman Catholic or being an atheist would not mean you were outside the Reformation, any more than being a Frenchmen living in Washington DC from 1860 to 1865 would put you outside the Civil War (That analogy probably works more closely with the atheist. Sorry. I’m in a hurry.)

I didn’t start this post intending to mention this, but it would be interesting to interview secular (including atheist) and Christian historians and ask if there is a difference between “church history” and “cultural history.” I think the secular historians would think you must be silly to even ask such an impossible question. But there may be one or two Christian historians who insist that they are entirely separate.

Thomas Jefferson would laugh at such a wall.

PS.  Why I wrote “another note”