To those interested in the historiography of Davidic genealogies I recommend the book: This Noble House by Arnold E. Franklin (U. of Pennsylvania, 2012): Using mostly documents uncovered in the Cairo Geniza, Franklin has come up with a list of 107 Davidic dynasts (Appendix B) that are documented from the Middle Ages (between the 10th and 15th centuries). Most of these dynasts then rely on the Seder Olam Zuta, a Davidic pedigree dated to late
eighth- or early ninth-century Iraq to trace their connections to earlier times, going as far back as David himself. Franklin summarizes the situation with regard to pedigree shown in the Seder Olam Zuta as follows: "The general consensus among historians is, in fact, that Seder ʿolam zuṭa was mostly likely composed during the Islamic period with the goal of defending the exilarchs against the attacks of rivals who called into question the legitimacy of their purported pedigree. It is, in the words of one historian, an attempt to “fabricate. . . a precise lineage connecting the Exilarch with the last kings of Judah. By means of the list embedded in Seder ʿolam zuṭa’s narrative, nesiʾim living in the tenth, eleventh, and twelfth centuries would ultimately be able to trace themselves back to their mythic forebear as well. So valuable, in fact, was the genealogical sequence devised by its editors that it was incorporated into practically every subsequent effort to prove an individual’s descent from King David in the Middle Ages, the genealogy copied by Abraham al-Raḥbī being no exception.” p.72. So it seems that any attempt to connect modern dynast with the biblical past will confront this insurmountable wall. Nevertheless, I have taken the time to examine the modern lines vis a vis the historical dynasts presented by Franklin. The Dayan of Aleppo pedigree does match up with one of Franklin's dynasts: #25 in Franklin's Appendix B is David ben Daniel, whose ggf, Shlomo ben Yesheyahu (bca 937 CE), is also a direct patrilineal ancestor in the Dayan pedigree. Shlomo's father is Yesheyahu ben Zakkai, brother to David ben Zakkai ("David II took power (921) his brother Josiah (Al-Hasan) was elected anti-exilarch in 930, but David prevailed. Son of Zakkai" from https://en.wikipedia.org/wiki/Exilarch). So, at least there is confirmation that the Dayan pedigree conforms to the Middle Age genealogies. I have not found corresponding lineages for the other modern dynasts in Appendix B. The other dynasts connect to Seder Olam Zuta at earlier periods: the Abravanel line stems from Bustenai (ca 650 CE), the Shaltiel, Benveniste, and Yakhia lines stem from Nathan bar Abba Mari, 21st Exilarch Nathan II (ca 375 CE). What this means is that the Dayan line has the greatest amount of historical support connecting it to documented dynasts from the middle ages, but as summarized by Franklin, historians doubt the accuracy of the Seder Olam Zuta prior to Bustenai ca 650 CE. The only strategy to confirm a Davidic line beyond Bustenai would be to use ydna, as has been done with the Cohanic tree, and to see if a certain ydna haplogroup is more frequent than any other in modern persons believed to be dynasts. However, unlike with Cohanim, there are relatively few persons around today who are able to reasonably claim Davidic descent so it will be difficult to obtain the same depth of data as has been done with Cohanim. As noted elsewhere, the ydna so far gathered from modern dynasts shows no modality regularity. Confirmation of any modern dynasts pedigree beyond Bustenai must await a data breakthrough.
