The narrator of the text says that, after the tenth year, the lawyer only read the New Testament. Therefore, it sounds as though he began to read this section of the Christian Bible in the eleventh year of his voluntary imprisonment.
During the first year, the lawyer mostly read books that had "a light character": love stories, crime and fantasy, comedy, and the like. It almost sounds like he wanted the kind of books that would transport him, distract him, or entertain him, dispelling any boredom or dread he might feel. In the second year, the lawyer asked for "the classics," which he presumably read for at least a couple of years until the fifth year, in which "he did not read" at all. He played a lot of music and drank a lot of wine that year.
During the sixth year, the lawyer began to study history, philosophy, and world languages, and he read approximately six hundred volumes in the next four years. It is after this prolific period of reading that the lawyer ceased his voracious consumption of books and simply read the New Testament for "nearly a year," though it was "easy to understand and by no means thick." This greatly surprised the banker. It would imply that the lawyer found a great deal to consider or think about as he was reading this text. This period was followed by an era in which the lawyer read about the history of world religions and theology and then a final "haphazard" and seemingly random assortment of various genres, subjects, and titles.