The word.......SSSSSSSSSTTTTTTTTRRRRREEEEETTTTTTCCCCCCHHHHHHHHHHHHHH really comes to mind............WOW
He should of bought the gospel truth rather than selling it seeing no value in the spiritual things not seen rather than killing the messenger. His punishment cursed from the earth and no rest in his work was more than he could bear. The Sabbath rest that Christ did bear for his brother whom he murdered .
There is not one reason why we should look for a literal mark. .John who penned it knew the mark was the mark of Cain (666) natural unconverted man.
The idea that it stayed a mystery until smart techknowolgy advanced is not taught in the bible .