There exist some versions. One of them tells about the Rabbi Meshullam Kusi Rapa ha-Kogen Tsedek who lived in the Rhine province of the Middle Ages Germany in the fifties of 15th century. He had «Rabbi d’Oporto» nickname, i.e., a rabbi from Portugal. The ancient seal of the kin people of Rapa ha-Kogen Tsedek contains the design of a Raven together with two hands folded for blessing. The symbolic Raven is pronounced as Rappe in Mid Upper Germanic Dialect (ModGerman as Rabe).

Another version considers that the formation of this surname due to the marriage of those people, whose nicknames in the Germany of the Middle Ages were Rapa (Rappe ha-Kogen) and Porto (people who come from Portugal).