The descendants of Japheth become the outliers of the Old Testament. Noah tells his son that his descendants would "dwell in the tents" of the Semites. Before that would happen, though, most of the Semites would be assimilated into the Japhethites after Assyria forced the tribes of the northern kingdom (known at the time as "Israel") into the intermarrying with surrounding peoples.
After the Assyrians (a Semitic people) were taken over by Babylonia (a Hamitic people), the Medes (Madai) people would join with the Persians (Elam, another Semitic people) to rule until Alexander, a Macedonian (a Greek (Javan). Jews, both Semitic and proselytes, would come to Jerusalem on the feast days if they could make it. Many Japhethic citizens are mentioned as being in Jerusalem at the "birth of the Church" in May of AD 33.
Finally, the Apostle Paul would begin a campaign to take the Gospel -- the final message to all true "sons of Abraham" -- to those who had been despised since the giving of the Law: the "Gentiles" (aka "nations" or "pagans") The term "Greek" would become synonymous with "Gentile." The second generation of Christians were almost entirely Gentiles. At long last, the Japhethites would "dwell in the tents" of the Semites.