thumb|A 1466 edition of [[Antiquities of the Jews]]
Flavius Josephus was a first-century Jewish historian who provided external information on some people and events found in the New Testament. Josephus was a general in Galilee, which is where Jesus ministered and people who knew him still lived; he dwelled near Jesus's hometown of Nazareth for a time, and kept contact with groups such as the Sanhedrin and Ananus II who were involved in the trials of Jesus and his brother James. His knowledge of Galilee was notable since he wrote much about that region and its inhabitants in his autobiography The Life of Flavius Josephus which was an appendix to Antiquities of the Jews, where the references to Jesus are located. The extant manuscripts of Josephus' book Antiquities of the Jews, written , contain two references to Jesus of Nazareth and one reference to John the Baptist.
The first and most extensive reference to Jesus in the Antiquities, found in Book 18, states that Jesus was the Messiah and a wise teacher who was crucified by Pontius Pilate. It is commonly called the '. The passage exists in all extant manuscripts of Antiquities. Since the late 20th century, the general consensus has held that the Testimonium is partially authentic in that an authentic nucleus referencing the life of Jesus was original to Josephus. Many modern scholars believe that an Arabic version that was discovered by Shlomo Pines reflects the state of Josephus' original text.
Modern scholarship has largely acknowledged the authenticity of the second reference to Jesus in the Antiquities, found in Book 20, Chapter 9, which mentions "the brother of Jesus, who was called Christ, whose name was James".
Almost all modern scholars consider the reference in Book 18, Chapter 5 of the Antiquities to the imprisonment and death of John the Baptist also to be authentic and not a Christian interpolation. A number of differences exist between the statements by Josephus regarding the death of John the Baptist and the New Testament accounts. Scholars generally view these variations as indications that the Josephus passages are not interpolations, since a Christian interpolator would likely have made them correspond to the New Testament accounts, not differ from them. Scholars have provided explanations for their inclusion in Josephus' later works.
Extant manuscripts
thumb|upright=0.85|A 1640 edition of the Works of Josephus
Josephus wrote all of his surviving works after his establishment in Rome () under the patronage of the Flavian Emperor Vespasian. As is common with ancient texts, however, there are no known manuscripts of Josephus' works that can be dated before the eleventh century, and the oldest which do survive were copied by Christian monks. Jews are not known to have preserved the writings of Josephus perhaps because he was considered a traitor, or because his works circulated in Greek, the use of which declined among Jews shortly after Josephus' era.
There are about 120 extant Greek manuscripts of Josephus, of which 33 predate the fourteenth century, with two thirds from the Komnenos period. The earliest surviving Greek manuscript that contains the ' is the eleventh-century Ambrosianus 370 (F 128), preserved in the Biblioteca Ambrosiana in Milan, which includes almost all of the second half of the Antiquities. There are about 170 extant Latin translations of Josephus, some of which go back to the sixth century. According to Louis Feldman these have proven very useful in reconstructing the Josephus texts through comparisons with the Greek manuscripts, confirming proper names and filling in gaps. One of the reasons the works of Josephus were copied and maintained by Christians was that his writings provided a good deal of information about a number of figures mentioned in the New Testament, and the background to events such as the death of James during a gap in Roman governing authority.
Slavonic Josephus
The three references found in Book 18 and Book 20 of the Antiquities do not appear in any other versions of The Jewish War except for a Slavonic version of the Testimonium Flavianum (at times called ') which surfaced in the west at the beginning of the twentieth century, after its discovery in Russia at the end of the nineteenth century.
Although originally hailed as authentic (notably by Robert Eisler), it is now almost universally acknowledged by scholars to have been the product of an eleventh-century creation as part of a larger ideological struggle against the Khazars. As a result, it has little place in the ongoing debate over the authenticity and nature of the references to Jesus in the Antiquities. Craig A. Evans states that although some scholars had in the past supported the Slavonic Josephus, "to my knowledge no one today believes that they contain anything of value for Jesus research".
Arabic and Syriac Josephus
In 1971, a tenth-century Arabic version of the ' from the chronicle of Agapius of Hierapolis was brought to light by Shlomo Pines, who also discovered a twelfth-century Syriac version of the ' in the chronicle of Michael the Syrian. These additional manuscript sources of the ' have furnished additional ways to evaluate Josephus' mention of Jesus in the Antiquities, principally through a close textual comparison between the Arabic, Syriac and Greek versions to the Testimonium.
There are subtle yet key differences between the Greek manuscripts and these texts. For instance, the Arabic version does not blame the Jews for the death of Jesus. The key phrase "at the suggestion of the principal men among us" reads instead "Pilate condemned him to be crucified". Instead of "he was Christ", the Syriac version has the phrase "he was believed to be Christ". Drawing on these textual variations, scholars have suggested that these versions of the ' more closely reflect what a non-Christian Jew might have written.
Potential dependence on Eusebius
In 2008, however, Alice Whealey published an article arguing that Agapius' and Michael's versions of the ' are not independent witnesses to the original text of Josephus' Antiquities. Rather, they both ultimately derive from the Syriac translation of the Ecclesiastical History written by Eusebius, which in turn quotes the '. Whealey notes that Michael's Syriac ' shares several peculiar choices of vocabulary with the version found in the Syriac translation of the Ecclesiastical History. These words and phrases are not shared by an independent Syriac translation of the ' from Eusebius' book Theophania, strongly indicating that Agapius's text is simply a paraphrased quotation from the Syriac Ecclesiastical History, and not a direct quotation of Josephus himself. Michael's text, in contrast, she concludes is much closer to what Josephus actually wrote.
One of the key prongs in her argument is that Agapius' and Michael's ' share the unique peculiarity that they both explicitly state that Jesus died after being condemned to the cross, while the Greek original does not include this detail. According to Whealey, the differences between the two ' are simply due to the fact that Agapius' chronicle more freely paraphrases and abbreviates its sources, whereas Michael's version is probably a verbatim copy. The implication of this argument, if valid, is that Agapius' abbreviated ' cannot be an earlier version of the passage than what we find in extant manuscripts of Josephus' Antiquities.
Whealey furthermore notices that Michael's version of the ' shares common features with Jerome's Latin translation. Most importantly for her, instead of "he was the Messiah", as in the Greek ', Jerome's and Michael's versions both read, "he was thought to be the Messiah". She considers it likely, therefore, that the Latin and Arabic translations go back to an original Greek version with the same reading. Since they otherwise have no substantial disagreement from the Greek version we possess, and since that sole variant is sufficient to explain the most powerful objections to the 's integrity, she concludes that it is "the only major alteration" that has been made to what Josephus originally wrote.