Who came first, Senator Elizabeth Warren or Senator Bernie Sanders?

Actually, neither came first.

They each developed their own policies quite on their own. 

Senator Sanders was well versed in public policy from the time he was mayor. 

Senator Warren had the path of learning and teaching. She decided on politics when the country was obviously heading down the wrong path. 

But, to say Senator Sanders popularity is because Senator Warren speaks out is not at all accurate. They both have their own decision tree. It is interesting though how very close their policies are regardless of their independent development.