Japheth was the oldest of the three sons of Noah. Born about 100 years before the Great Flood, he would take a wife to bring upon the ark sometime before the doors were closed. They would have seven children after the flood.
Some time after the flood, when his father had become a farmer, his younger brother Ham came to him and Shem , speaking evil of their father. Taking Ham at his word, his brothers devised a way of covering their naked father without having to look upon his unclothed body.
Based on the names of his sons and other descendants, his people migrated north away from Babel after the confusion of tongues. Theirs would be what would become known as the Indo-European languages.
Ancient "genealogy" tables portend to list names going back to his descendants, the founders of eastern European nations, as well as verifiable migrants from those nations (such as the Scottish tribes). Biblical descendants of Japheth would be the Greeks (Javan), the Medes (Madai), and the Romans.