Chares of Mytilene in Wikipedia

Chares of Mytilene (Ancient Greek: Χάρης ὁ Μυτιληναῖος) was a Greek belonging to the suite of Alexander the Great. He was appointed court-marshal or introducer of strangers to the king, an office borrowed from the Persian court. He wrote a history of Alexander in ten books, dealing mainly with the private life of the king. The fragments are chiefly preserved in Athenaeus. See Scriptores Rerum Alexandri (pp. 114–120) in the Didot edition of Arrian.