Take this case, the Czechs: in the 8th and 9th centuries, the West Slavic peoples (Poles, Czechs, Slovaks, Kashubs, Sorbs, etc) split from the East Slavic people, but they didn't differentiate among themselves until well into the late middle ages.
The first to get a definition of nationhood were the Czechs, who were the westernmost who "got civlization" from the Germans (who in turn had got it from the Romans.
They Christianized first and sent missionaries to the Polans, Vistulans etc.
But, tying yourself to a higher culture (the Germanic one) is always difficult -- you can get swamped. And that's what happened to the Czechs. They saw the wealth and prestige of the Holy Roman (German) Empire and wanted to be part of it, ending in the 14th century when their King was made King of the Romans.
The Poles on the other hand kept their distance -- their king was crowned a king by the holy Roman Emperor and later, when the Piast (the first) dynasty died out, they didn't join with the Hapsburgs but with the erstwhile pagan Jagiellons (Lithuanians), but that is another story
When you tie yourself to a stronger, richer culture, you get swamped, even if you are the ones who "conquered" the other (see what happened to the Manchu/Jurchens after they conquered China in the 17th century
Hus was a reaction against the Germanizing influence. The religious angle came secondary imho
For Luther, I believe that the aim of the northern Germanic princelings to break away from the HRE also played a big role
If one doesn’t have a personal relationship with Christ Jesus they won’t know for sure. Otherwise, salvation would be like a roulette wheel. Depending on when and where you died, and if you had time to set everything right.
He is holding me in the palm of His hand and He said no one could take me out. I have no trouble believing that. Just make sure your trusting His blood to wash you clean from your sins. Ask Him to help you love and know Him. He will. Salvation is a love story it is a heart matter, having not much to do with the head. You can’t learn it with the head only and be saved.