I'm watching the Barbara Walters "Finding Your Roots" episode right now, and it says his name was Tzvi Getzel Waremwasser. We're showing Hersz Getzel Warmwasser.
The discrepancy in the surname is normal enough, but are Tzvi and Hersz interchangeable?
Here's info from the "Finding Your Roots" book: https://books.google.com/books?id=IDVcBAAAQBAJ&pg=PA50&lpg=...