Besides the books contained in the New Testament, many other writings from the first century or so of the Christian church are known to have survived, or are quoted or referred to by later writers. These writings include gospels, letters, narrative books like the Acts of the Apostles, apocalypses, and collections of teachings. In some cases these works provide direct evidence of teachings that were later rejected by the main body of Christians. In other cases they contain similar material, or parallel arguments, to those in parts of the New Testament, such as the instructions to local churches in the Pastoral Letters. In still other cases they provide further examples of kinds of literature found in the New Testament, such as gospels, acts, and apocalypses. Early Christian writings discussed in this glossary are: the Letter of Clement, the Didache, the Letters of Ignatius, the Letter of Polycarp, the Gospel of Thomas, the Shepherd of Hermas.