Sentence:  Patriarch of Jerusalem, Theophanes, who in October of that year [said] of the Cossacks: "We all know about the Cossacks, that these chivalrous men are of our race, are of our kin, and are true Orthodox Christians...They are the descendants of the glorious Rus&#39;, of the seed of <WSD>Japheth</WSD> who fought Byzantine Greece on land and on sea." 
Meaning of the word marked with <WSD> tags:  The third son of Noah, brother to Shem and Ham, who received a blessing from God with Shem, considered to be the ancestor of the Japhetic people(s) (associated approx. with Indo-Europeans).