It was one of Steven Nadler’s books on Spinoza which described the tri-party religious conflict of Europe’s Thirty Years War thus: The Roman Catholic Church believed that the Eucharist was through the miracle of Transubstantiation, in actual fact the body of Jesus Christ. The Lutherans taught that the Eucharist was merely the spiritual presence of Jesus Christ. Calvinists taught that the Eucharist was nothing more than a symbol of Jesus Christ.
And so, eight million people fought for, killed for, and died for the “superiority” of their individual religious beliefs. Some things never change.