>>509647464
>somehow not following modern rabbinic rules on matrilineal descent
They followed mat
There was probably a shortage of Jewish women in the Jewish communities of Italy/Greece, as the Jewish population in those areas was arguably skewed towards male merchants.
The Jews in those communities solved that problem by marrying the already existing God-Fearer local women, converting them convert to Judaism beforehand according to the Halakha rules, it was all kosher.