There was a huge push in the late Renaissance through the Victorian era for rulers in Europe to somehow establish a religious authority of their rule or country by claiming some sort of descent from Israel or the early church. They wanted to prove their nation was ordained by God and in many cases, made up entire lineages and histories. Many of these are still being used a source material in modern Anglo-Israeli type groups and beliefs. For example, the Scottish historian(sic) Sir Lawrence Gardner has written and documented extensively from these old documents how Scotland was actually the 'new Jerusalem' and the Scottish kings were the rightful rulers of Britain through such (as well as a bunch of other nutty connections.)
It makes for fascinating fiction, but only if you understand it as such and the motivation behind it.
I think the actor Yaphet Kotto comes from an African tribe that bought into the lost tribes mythology the English missionaries pushed.
I read somewhere that geneticists also doubt the science behind the Lemba of South Africa and the Cohen gene but I am going by memory on that one. The Lemba also only stared to talk about being a Lost Tribe of Israel only after British missionaries told them that they were.
Now you also have actual Jewish rabbies going to these self identified 'lost tribes' and 'converting' them as well - also for political reasons.
I’ve seen a “genealogy” of my own paternal line, going back from England, to Wales, to Ireland, to Milesia/Spain, to Scythia and eventually to Japheth, son of Noah.
These things were quite fashionable at one time.
It’d be great to have my line firmly established that far, lol, or even beyond the 1400’s, but the plague years really wrecked record keeping, and people were forced to move around, uncharacteristic for the time.
All I have from before then, is the earliest known recorded instance of the surname, from the presumed progenitor, found in the Templar Inquisition of 1185.