How did the Catholic reluctance to read the Bible begin?

Prior to the Reformation, Catholics were not reluctant to read the Bible. Those Catholics who were educated were able to center their spirituality around the Bible. I am thinking of outstanding Scripture scholars like Origin, Jerome, and Augustine. Thomas Aquinas based his theology on a deep understanding of the Bible. Until the printing press was invented, education of the masses was at a very low level in comparison to today. Handwritten copies of the Bible were difficult to produce. Because these copies were so few and precious, they were often chained to the lectern in a church to make sure they were not stolen. At this time, a style of Christian living arose in many places in the church that didn't seem to be in agreement with the Scriptures: clericalism was rife, there were the money-making indulgences, avarice, papal military power, good works more important than faith; and an impersonal ecclesiastical bureaucracy often stifled the freedom of the Spirit.

The reformers revolted against all this and based their actions on various verses of the Bible. Once the Bible was translated into the vernacular and Mass produced by the newly invented printing press, education of the masses improved, and people could read firsthand the arguments of Luther and the other reformers. Christianity was divided into two camps: the Protestant camp, those who thought the Bible was the sole authority in religious matters; and the Catholic camp, those who thought the Pope together with Tradition and Scripture was the sole authority.

Catholics moved to the defensive. Catholic authorities greatly feared "private interpretations of the Bible." Although the Bible had been and was still the Word of God, the free reading and private interpretation of the Scriptures by Catholics were restricted. The interpretation of the Bible was kept in the hands of clerics. The laity were told to be cautious lest they misread the Bible as the reformers had done. Fortunately, today, Catholics are encouraged to read and study the Bible.