Homer Nods Meaning

(idiomatic) Even a great person makes mistakes.

Example: 1677 "Horace acknowledges that honest Homer nods sometimes" (Dryden, Preface to The State of Innocence[1])
1709. Alexander Pope, Essay on Criticism (poem):
  Those oft are stratagems which errors seem, Nor is it Homer nods, but we that dream. ([2]Essay on Criticism)
1713 "He knows that Homer nods sometimes, and that Faults are found in the best writers." (N. Rowe, A Defence of M. de La Bruyère p. p. 102)
2009. James Taranto, Wall Street Journal, When Pigs Flu, April 27, 2009 [3]:
  And Homer nods: The Arizona Cardinals and Philadelphia Eagles played in this year's NFC championship, not NFL championship as we said in a Friday follow-up (since corrected).