Historicists believe that revering (forehead) and obeying (right hand) the Popes, knowingly, is the Mark. Billions of people do this, though unknowingly as of right now (Catholicism had not become mandatory yet). WWIII, however, will force people to see Rome for what it is: Mystery, Babylon the Great, the city upon seven hills. People will leave Catholicism for anything that isn't Papacy-approved.

The Jesuit Order thought of this (since they're the ones who contrived it), and will enforce Catholicism as the one-world religion. This will be the Mark of the Beast. People will know it, and most won't accept it, knowing how this works. Here are some ways you take the Mark by obeying the Pope: Saturday or Sunday Sabbaths instead of lunar Sabbaths, futurism or preterism instead of historicism, practicing Zionism, communism, or National Socialism, and reading Bible versions overseen by the Vatican (NIV, ESV, LST, NLT, NJKV, NASB, even ASV to name a few) to monkey with the Word of Yevah.