There are two basic ways to capture a nation. Force of arms or control of the economy.
I do not know about Calvin by one of Martin Luther's main goal was to stop the flow of wealth from Germany to Rome. Indulgences was what he was attacking and trying to stop. He did not want Rome to control Germany's economy.
Do you have evidence that Luther's objection to indulgences was secular rather than spiritual?
Sure, but it's hard to call Christendom and the Ummah "tribes" without (as I said earlier) stretching that term into meaninglessness.