(Νικόμαχος), a scribe at Athens (γραμματεύς), rose to citizenship from a servile origin, if we may believe the statements in the speech of Lysias against him. According to the same authority he was entrusted with a commission to transcribe the laws of Solon, a period of four months being allowed him for the purpose ; but he extended the time, on various pretences, to six years, and drove a profitable trade by tampering with the laws, in the way of interpolation or omission, as it suited his several employers. In particular, he lent himself to the intrigues of the oligarchical party, in B. C. 405, and fabricated a law giving power to the council to take cognisance of the alleged offence of CLEOPHON. Notwithstanding, however, his services to the oligarchs, he was obliged to fly from Athens under the government of the Thirty. On the re-establishment of democracy he seems to have been again employed in the transcription and registering of the laws, and it was for misconduct in the execution of this duty that he was visited with the prosecution for which the speech of Lysias was written. (Xen. Hell. 1.7.35; Lys. c. Agor. p. 130, c. Nicom.) It was perhaps the same Nicomachus who is mentioned by Aristophanes (Aristoph. Frogs 1502) as a ποριστης --one of those whose business it was to levy extraordinary supplies (see Dict. of Ant. s. v.) --and to whom Pluto is made to send, through Aeschylus, a present of a rope, with an urgent demand for his early appearance in the regions below. The Nicomachus also mentioned by Isocrates (c. Callim. pp. 373, 374) may, perhaps, have been the same person.
[E.E]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890