Some general background on Emesa/Treves from Marshall Kirk (1998)

Kelley’s [Emesa/Treves] hypothesis is that certain families descend from certain earlier families, without specifying most of the exact individuals through whom the descent passes. (I don’t think the evidence exists to do this.)
I feel fairly comfortable in saying the following about the hypothesis. Iduberga is certainly Charlemagne’s ancestress. I see no good reason to reject the genealogical -- as opposed to hagiographical -- details of the vitae sanctorum that say she was sister of Modoald, Bishop of Treves, as well as one Severa, and aunt (or mother?) of Modesta. The latter name -- rare, by then -- suggests descent from Modestus, Bishop of Treves (d. ca. 486). Close analysis of the Treverian episcopal list is suggestive, but falls short of proof -- and always, I think, will. Specifically, some of the later bishops have names which seem to link them with some of the earlier; similar linked pairs (or groups) of names occur in the fasti of other bishoprics, where relationships in some cases are attested. Some of the names -- especially and specifically Iamblichus and Himerius -- are characteristically Syrian, and, in the former case, royal Emesan and very rare. An early bishop of Treves -- Agroecius (...312-ca. 332) -- is explicitly stated -- again, in a vita -- to have been, previously, a priest at Antioch [Syria]. His name recurs on the gravestones of Treves; also, later on, in the fasti of other Gallic bishoprics, in an onomastic context suggesting a marital connection -- presumably at Treves itself ca. 340 -- with the family of St. Ambrose.1  We know, from a contemporary statement, that a Treverian bishop shortly prior to Modoald -- Magneric -- was a descendant of Tetradius, a rich man of “proconsular” rank, at Treves -- perhaps as an official in the government of Magnus Maximus -- ca. 385. We can assume, but with a fair degree of confidence, that the onomastically Syrian Treverian bishops of the mid-Vth century were descendants of the century-earlier Syrian Agroecius.
All this, and more, strongly suggests -- but does not prove -- that the episcopal throne of Treves, as of so many other sees, was monopolized for two or three centuries by, if not one group of agnate kin, at most a very small number of interlinked families. Descent from a late member of one of these families strongly implies descent from most of the early ones. (Just as recent descent, in New England, from a Winthrop, or a Saltonstall, or a Leverett, strongly implies descent from, as well, Thomas Dudley, not to list a goodly number of other first-generation colonial magnates.) It’s a good bet that Modoald and Iduberga were descendants of Tetradius and Agroecius; but exactly how can’t be shown. We know nothing at all about most of the bishops on the list save their names and approximate floruit; most were the subjects of no surviving vitae.
The situation is complicated by the fact that Tetradius is a pagan, who converts only ca. 385; the earlier Agroecius is, of course, a Christian. I have guessed that Bishops Iamblichus and Himerius descend from the pagan Neoplatonist Apamean family that bears these names, in the male line, via Tetradius; from the Christian Agroecius, and from the Bishops of Lyons -- who the earliest instance of the name Tetradius -- in the female line. This is reasonable, as the late IVth-century aristocracy saw a number of ‘mixed marriages,’ with pagan husband and Christian wife; but I don’t know of any cases vice versa. Intuitively, I suspect that Christianity was seen by many as a more suitable religion for women than for men, anyway -- too passive, meek, and mild in its values (too sickly and emasculated, in fact, in a sort of Preraphaelite way, as depicted in, say, the works of Gregorius of Tours) to suit most red-blooded men, who no doubt saw in such sanguinary rites as the taurobolium a confirmation of their essential virilitas. Today, we have football, or real war, but the principle’s the same.
At an earlier date -- to skip over other areas of uncertainty, between times -- scholars seem agreed that the ‘Emesan women’ (Domna, Maesa, Soaemias, Mamaea, b. say 155 to 180) of the imperial Severan dynasty descended from the last known king of Emesa, C. Julius Sohaemus, the rex magnus (d. ca. A.D. 73); but no-one knows how, as there are no relevant literary sources. This leaves a gap of about five or six generations. Using Emesan funerary inscriptions, which often specify the year (in the Seleucid era) and/or the name of the decedent’s and/or tomb-dedicator’s father, I’ve constructed a tentative pedigree that crosses this gap; but it’s quite conjectural, and a couple of questions arise as to whether some of the individuals’ prefixed Roman nomenclature, stemming presumably from the process of libertas, could, technically, ‘fit’ that of the others. It’s beyond my competence to determine.
Similarly, a ‘Nesrosamsos’ of Emesa, adult in 99, and apparently of the royal house, or a hypothetical homonymous nephew, may or may not (again, this is my thought) lie behind the ‘Nasoros’ and/or the ‘Nassumos’ who were great-great-grandfathers of Odaenathus and -- probably -- Zenobia of Palmyra ... who seem likely, on historical grounds, to have had some descent from the earlier and more prominent Emesan house, anyway. It would take a philologist with expertise in ancient Syriac -- or is it Phoenician? -- to give a qualified opinion.
1. Although Iím at a loss to say how this occurred. Ambrose and his two siblings are all thought to have died unmarried and childless. Unless this represents hagiographical suppression of an early marriage for Ambrose -- surely a radical idea, since his sister Marcellina was a major source for his vita -- then an aunt or uncle of Ambrose may have married a child of Agroecius. But this would not convey the names Uranius and Satyrus to Ambroseís bashful brother.