These denominations all derive from The Reformation which was a movement against the abuses of the Catholic church to restore the true Gospel which had been greatly obscured. A big part of it was translating scripture into the common tongue and getting it into the hands of people for the first time. Martin Luther really kicked things off by nailing his "Ninety-five Theses" critique to the door of a church. If you really want to know the core tenants, here is a complete, concise summary of reformed Christian doctrine: https://matt2819.com/wsc/ The various protestant denominations differ in various distinctives and modes of worship.