As far as I’m aware, the Kahn line has modern-historical origins primarily in Ashkenazim Jews (those settling in northern Europe, especially Germany, Poland and Russia) but we also have a link through marriage with Sephardim Jews (those who settled in the Iberian Peninsula).
Moses Gomes Silva (1786-1858) married in 1824 Elizabeth Bathsheba Mesquitta (1805-1875) both of whom have their roots in Portugal although their ancestors appear to have migrated to Jamaica to escape persecution, perhaps as early as the 17th century.
Moses and Elizabeth had several children, including Esther Gomes Silva who became the second wife of Isaac Moses Marsden, bearing him quite a bunch of children, including Madeline Moses Marsden (1846-1880) – and she was married in 1867 to Salomon Fallek (1838-1893).
Salomon and Madeline had several children, including Eugenie Fallek and she married Arthur Kahn, one of the sons of Victor, or Great Uncle Arthur as we are wont to call him.
A few years ago I ordered from the USA a difficult-to-find book on Jewish European history, but the seller sent the wrong one and in the meantime sold the one I wanted to another customer. The book they sent (and allowed me to keep while giving a full refund – very generous) was “A History of the Marranos” written by Cecil Roth and published in 1932. Marranos was the name ascribed to those Spanish Jews professing to convert to Christianity to escape the terrors of the Inquisition while in secret continuing to practise their true faith. Many went from Spain to Portugal and then emigrated to the New World. The book settled dustily on my bookshelf unread until I became aware we have connections to Spain and Portugal. The deckled pages have taken on a new lease of life as I turn them slowly, hoping to find a reference pertinent to our extended and growing family, so far without success. However, it does help to put into perspective (or present a different viewpoint on) even today’s religious imbroglio. If I find anything of special scientific interest to our family’s concerns, I shall of course post them here.
I’ve been looking with no luck for ancestors of Hyman Benjaman Kahn who was born before 1869 in Russia.