There is not a lot written in the holy scriptures of Japheth, however, his sons are listed and reveal some things of his descendants. There are several secular writings which are of him and even more that are believed to be him even though the language differences make the spelling leave room for question.
There are differences of opinion as to whether Shem or Japheth was the eldest of Noah’s sons. There seems to be little reason to care. They were normally referred to as Shem, Ham and Japheth, which, according to Hebrew custom, would start with the eldest and go to the youngest. However, others feel that Ham was the youngest due to the episode recorded in the Bible of his seeing his father naked and drunken. And yet, still another writing, if accurate and actually does refer to these men, has Japheth as the firstborn of Noah.
There are adequate writings and archeological evidences to assure that Japheth was the origin of many (perhaps all) in the Indo-Aryan and Euro-Aryan peoples. Thus the Indian race as well as the Caucasians are of his descendants.
Genesis chapter 10 and verse 2, gives the sons of Japheth’s names as Gomer, and Magog, and Madai, and Javan, and Tubal, and Meshech, and Tiras. Also, chapter 10 describes the progeny of both Gomer and Javan and makes this statement:
“By these were the isles of the Gentiles divided in their lands; every one after his tongue, after their families, in their nations.” (Genesis 10:5 KJV)
The Greek writings and legends trace their lineage back to a man named Japetos which is reportedly their spelling of Japheth and the Indian branch of the Aryans, also trace their ancestry back to the same man. In the Indian account of the flood, they spell Noah as Satyaurata whose oldest son was named Jyapeti.
Although these two branches of the Aryan people have been shown to be descended from Japeth, and more specifically from his sons, Gomer and Javan even though there were numerous wars and shifting of locations that some mixed breeding occurred. Yet, seemingly they maintained a large amount of their ancestral appearance.
For a more detailed history of the descendants of Japheth, Click Here.