This graph of ' lineage [right column] is a historical reconstruction based on information in the opening paragraph of his autobiography & other works. He claims to have recorded his genealogy "as I have found it described in the public records" [ 1]. But when coordinated with historical information about the that he himself reports in his other works [left four columns] there are some obvious major generational discrepancies in his family tree. Josephus' count of his ancestors' generations would make him a fourth cousin of 's 2nd wife, , who died sixty-eight years before he was born! Josephus' reports of his own experiences make it more probable that he was at most a sixth or, more likely, a seventh cousin of his near contemporary Herod , who was king of Iturea [southern Lebanon] in the decades surrounding the Jewish-Roman war of 66-70 CE.
Either Josephus' memory or his family records were clearly confused. He begins by claiming: "My grandfather's father was named Simon, with the addition of Psellus," but goes on to represent this Simon Psellus as his "grandfather" Joseph's great-grandfather. Even so, he does not list enough generations between himself & Simon's grandson [Matthew Curtus], if he is correct in claiming that the latter was born the first year that was high priest. According to Josephus' dating, this Matthew's "son" Joseph would have been born when Matthew was 66. While not impossible, it is more likely that Josephus or some previous scribe overlooked a generation "in the public records" of the priestly courses of . This would have been particularly easy to do, if Matthew Curtus' son & grandson were both named Joseph.
Josephus was probably correct in recalling that his own grandfather was named Joseph. But he is just as probably mistaken in identifying his grandfather with Matthew Curtus' son (or grandson) Joseph. There is no good reason to question Josephus' report that his own father, Matthew, was born in the last year of ' reign [6 CE]. But in order for this Matthew to be the son of a Joseph who was born in the last year of Queen 's reign [68 BCE], the father would have been 74 years old when he sired a son. While not beyond biological credibility, it is more likely that at least one or, more likely, two generations were dropped in Josephus' hasty recounting of his family's history at the beginning of his apologetical autobiography. Since Josephus recalled that his family repeatedly named fathers & sons alternately, Matthew & Joseph---witness himself & his father & Matthew Curtus & his "son"---it is quite possible that Josephus forgot or overlooked such a pair in his reckoning. One advantage of this solution to the chronological questions raised by Josephus' family tree, is that it allows Josephus to be put in the same generation as his chronological contemporaries.
There are three ways to interpret Josephus' report of his family history: skeptically, literally, or genealogically. Given the chronological gaps & Josephus' penchant for defending himself, it would be easy to reject his family tree as folklore or fabrication. But his insistence that he based it "on public records" makes this the least likely solution. Priestly lineage was zealously preserved by Jerusalem's conservative ruling aristocracy. Before the Jewish-Roman war, it was the basis of a priest's job & social position; and it was used to regulate the priestly courses for more than a century after the destruction of Jerusalem's temple. If Josephus was known not to be of Hasmonean lineage, it is unlikely that he would have dared to have publicized himself as such in writing to his contemporary detractors, who were vocal & many.
While a literal interpretation of Josephus' family tree is not beyond belief, it stretches the biological imagination & raises biographical questions that are historically unanswerable. Did the males of Josephus' family marry late or often? Did they remain sexually active in old age? Did Josephus come from a line of priests that was orphaned young? If so, who raised & trained them? If Josephus' forebears had such exceptional longevity when compared with the Hasmoneans & Herodians he uses to date their birth, why does he fail to mention it?
While the revised genealogical reconstruction of Josephus' ancestry presented above is beyond historical proof, it at least makes historical sense out of the information he presents. My experience in tracking down & filling in gaps in the family genealogy that I inherited from my own grandmother convinces me that this is the most plausible interpretation of Josephus' family data.