The Gospel of John is significantly different from the synoptic gospels, with major variations in material, theological emphasis, chronology, and literary style.[51] There are also some discrepancies between John and the Synoptics, some amounting to contradictions.[51] The gospel forms the core of an emerging canon of Johannine works, the Johannine corpus, consisting of the gospel, the three Johannine letters, and the Apocalypse, all coming from the same theological background and opposed to the "Petrine corpus."