Ἑλληνάρχης
From LSJ
μὴ ἐν πολλοῖς ὀλίγα λέγε, ἀλλ΄ ἐν ὀλίγοις πολλά → don't say little in many words, but much in a few words (Stobaeus quoting Pythagoras)
English (LSJ)
ου, ὁ,
A chief of the Greek community, title at Tanais, IPE2.423, al.
Greek (Liddell-Scott)
Ἑλληνάρχης: ὁ, ἄρχων τῶν Ἑλλήνων, ἄρχων ἐν Σαρματίᾳ, Συλλ. Ἐπιγρ. (προσθῆκαι) 2132d, e.