Thread: Parallel axis or Huygens–Steiner theorem

I've got a question about the Huygens–Steiner theorem, actually the name itself. Most sources say that the theorem was named after Christian Huygens and Jakob Steiner. The information is not precise though on whether they themselves prooved this theorem or whether someone else named it after them. I'd like to know for sure who formed the theorem and also I'd like some prooth supporting the clame. Quote from a book or something like that. Thanks a lot in advance.