Ponos  or Ponus  (Ancient Greek: Πόνος Pónos) is the personification of hardship or toil.
Family
Hesiod
According to Hesiod's Theogony (226–232), "painful" Ponos was the child of Eris (Discord), with no father, and the brother of many other personifications:
And hateful Eris bore painful Ponos (Hardship),
Lethe (Forgetfulness) and Limos (Starvation) and the tearful Algea (Pains),
Hysminai (Battles), Makhai (Wars), Phonoi (Murders), and Androktasiai (Manslaughters);
Neikea (Quarrels), Pseudea (Lies), Logoi (Stories), Amphillogiai (Disputes)
Dysnomia (Anarchy) and Ate (Ruin), near one another,
and Horkos (Oath), who most afflicts men on earth,
Then willing swears a false oath.Caldwell, p. 42 lines 226-232, with the meanings of the names (in parentheses), as given by Caldwell, p. 40 on lines 212–232.
Cicero
According to Cicero, Ponos's was called the son of the primordial gods, Nyx (Night) and Erebus (Darkness) and brother to other personifications:Cicero, De Natura Deorum 3.17 Their [Aether and Hemera's] brothers and sisters, whom the ancient genealogists name Amor/ Eros (Love), Dolus (Guile), Metus/ Deimos (Fear), Labor/ Ponus (Toil), Invidentia/ Nemesis (Envy), Fatum/ Moros (Fate), Senectus/ Geras (Old Age), Mors/ Thanatos (Death), Tenebrae/ Keres (Darkness), Miseria/ Oizys (Misery), Querella/ Momus (Complaint), Gratia/ Philotes (Favour), Fraus/ Apate (Fraud), Pertinacia (Obstinacy), the Parcae/ Moirai (Fates), the Hesperides, the Somnia/ Oneiroi (Dreams): all of these are fabled to be the children of Erebus (Darkness) and Nox/ Nyx (Night).Cicero, De Natura Deorum 3.17 Philosophy
The Cynics promoted living a life of ponos.
For the Cynics, this did not seem to mean actual physical work.
Diogenes of Sinope, for example, lived by begging, not by doing manual labor.
Rather, it means deliberately choosing a hard life — for instance, wearing only that thin cloak and going barefoot in winter.
Notes
References
Caldwell, Richard, Hesiod's Theogony, Focus Publishing/R. Pullins Company (June 1, 1987). .
Marcus Tullius Cicero, Nature of the Gods from the Treatises of M.T. Cicero translated by Charles Duke Yonge (1812-1891), Bohn edition of 1878.
Online version at the Topos Text Project.
