בראשית י:ב פירוש: רש״י, רמב״ן, רד״ק וטור הארוך

ותירס AND TIRAS — This is Persia (Yoma 10a).

THE SONS OF JAPHETH: GOMER. Scripture begins with Japheth for he was the oldest. After him, it mentions Ham [even though he was the youngest]²⁶³See Ramban above, 6:10. for Scripture wanted to delay the account of the generations of Shem in order to place side by side the two sections dealing with Shem’s children since it is important to dwell at length on the generations of Abraham.

בני יפת גמר, according to Rabbeinu Saadyah gaon, he was the founder of the nation known as Altrach.