In the sigmatic compounds of the Greek language, it is the root of the adjective which has imposed one of the three endings of the dative plural, <εσι, <εσσσι ou <έεσσι (μνηστηρσιν αναιδεσι vs ανδρασι δυσμενεεσσιν). Concerning the sigmatic nouns, the aoidos has ofen had a choice between <εσι, <εσσσι ou <έεσσι. If the place of words in the hexameter has its importance, rhythmical harmony of syntagms is also the matter.