It would be difficult to overestimate the revolutionary impact of the printing press of the Medieval world, just as today it is almost impossible to overstate the impact of the computer and the internet.

At first, the Roman Catholic Church leadership resisted translating the Bible out of the Latin Vulgate version. They feared that if it was translated into the vernacular (the everyday language that people spoke in their countries of origin, such as German or English), the common person would misinterpret it and develop a skewed version of Catholic theology. The Church knew these translations posed a threat to its power and authority.

However, as the Reformation took off and with it came Protestant translations of the Bible such as the Geneva translation, the Roman Catholic Church accepted the inevitable. They produced their own, authorized translation that accorded with Catholic theology, calling it the Jerusalem Bible.

Ultimately, as the printing press rapidly evolved into a technology that could print thousands and thousands of copies of a work with ease, the Church began to use the technology to produce and widely disseminate its own work. It also increased the power of the Inquisition. Part of its function was approving or banning works depending on their accordance with Church teachings. Scientists such as Galileo, for example, were put in front of the Inquisition and forced to recant if they published scientific works that had not received Church approval.

The first major project undertaken by Gutenburg was printing the Bible. The Bible continued to be the book most frequently printed -- it is still, in terms of the numbers of copies printed, the single best selling book in the history of the world. The Roman Catholic Church was not particularly enthusiastic over the wide dissemination of the Bible. In early modern Roman Catholicism, the laity were not encouraged to read the Bible. Instead, excerpts from the Bible were read in Latin (which was only understood by a small elite) as part of the Mass and then explained in the vernacular by the priest. Thus the Bible was only made available as mediated by the church hierarchy and within the context of the way the Roman church interpreted it.

Protestants developed the sola scriptura (salvation can be achieved by reading and following Scripture on one's own) doctrine, and were active in translating the Bible into vernaculars, using the technology of print to distribute it widely, and encouraging people to read it for themselves. This was viewed as heretical by the Roman Catholic church because it encouraged "private judgement." It was not until Vatican II in the 1950s that the Roman Catholic mass began to be said in the vernacular.

Thus the Roman Church disapproved of printing the Bible in the vernacular and, in some cases, in the Greek (e.g. I John 5.7 controversy) and responded to printing other books depending on the books -- they approved of printing the Church Fathers and many ancient works, and disapproved of works they thought heretical.