I was told to study Jean Calvin but later my friend told me it wasn't even on the test.
Should I still study it?
john* and yes it is. It's easier than martin luther's account in my opinion
It can be John or Jean Calvin (John is just the English translation,) and yes, you should know both Martin Luther and Jean Calvin. An exam question may specify whether you should write about a reformer from inside or outside of Germany so knowing both is important to answer the question properly.