When the steam powered printing press was invented in 1843, false teaching and false prophets were given the one thing that they needed to deceive the Body of Christ. It made their profane theology available to the average person, and their books crept into seminaries everywhere. It spread corruption far and wide, to every part of the earth.
Before the printing press, Christians only had the Bible to rely upon – with the guidance of the Holy Spirit. It was too difficult and expensive for ill-conceived commentary to get very far. And now, with the Internet, corrupt ideas spread at the speed of light.