as to what markers denote dates. For instance, some manuscripts of the (called the Helena-recension and unattested before the 13th century) refer to Christian festivals and observances that only originated after the 4th century. This does not account for all of the manuscripts and those that were created earlier do not mention the festivals. In Origen's (likely written in the 3rd century AD), Origen quotes Celsus as calling Jesus "son of Pantera," which would point to Celsus' knowledge of the or its source material. In his Incredible Shrinking Son of Man, Robert M. Price states that the Toledot Yeshu is "dependent on second-century Jewish-Christian gospel", and Alexander argues that the oral traditions behind the written versions of the might go all the way back to the formation of the canonical narratives themselves. It is unlikely that one person is the author, since the narrative itself has a number of different versions, which differ in terms of the story details and the attitude towards the central characters. Even individual versions seem to come from a number of storytellers. Some scholars assert that the source material is no earlier than the 6th century, and the compilation no earlier than the 9th century. Although individual anecdotes that make up the may all come from sources dating before the sixth century, there is no evidence that their gathering into a single narrative is that early. Some scholars, like Jeffrey Rubenstein, favour a later composition date, after the 7th century. The earliest known mention is an oblique mention by Agobard, archbishop of Lyon, , and then another mention by his successor, Amulo, . However, since Agobard does not refer to the source by name it cannot be certain that this is the . The source material for the can be said to derive from four sources: Jewish rabbinic literature canonical Christian scriptures; noncanonical Christian writings; pagan anti-Christian writings of the Roman period. The largest source of input to the seems to be anecdotes gathered from various parts of the Talmud and Midrash. These appear to be popular adaptations of material aimed against two Christian doctrines: the virgin birth and the ascension. Some of the Talmudic anecdotes are clearly fictitious or absurd, and some seem incompatible with each other or with known historical fact. In some instances, the Talmudic source of the is very obscure or of doubtful authenticity, and may not originally have been relevant