Extant second-century Christian literature is strongly biblical in content. When many literate Christians came to articulate an understanding of their identity, whether in inner-Christian settings or dispute with non-Christian Jews or pagans, passages from scripture often played an important role. The writer of I Clement, a text dated towards the end of the first century, assumes, like the writers of the New Testament, that central to any exposition of the Christian message are the scriptures, or what Christians came to call the Old Testament. For many years it has been suggested that Christians read their Bible, in particular the Old Testament, not only directly from biblical scrolls, but also from collections of citations or testimony books. Material looking like the canonical Gospels, the Epistles of Paul, and some other New Testament books appears to have been known and used by Christians in the first half of the second century.