In Greek mythology, Panoptes ("the all-seeing") was an epithet for both Helios and Argus. Argus Panoptes, (Argus "all eyes") was a giant with a hundred eyes. He was also the nymph Io's brother. He was thus a very effective watchman, as only a few of the eyes would sleep at a time; there were always eyes still awake. Argus was Hera's servant. His great service to the Olympian pantheon was to slay the chthonic serpent-legged monster Echidna as she slept in her cave (Homer, Iliad ii.783; Hesiod, Theogony, 295ff; Apollodorus, ii.i.2). Hera's last task for Argus was to guard a white heifer from Zeus. She charged him to "Tether this cow safely to an olive-tree at Nemea". Hera knew that the heifer was in reality Io, one of the many nymphs Zeus was coupling with to establish a new order. Greek mythology comprises the collected narratives of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ... An epithet (Greek and Latin epitheton; literally meaning imposed) is a descriptive word or phrase. ... This article is about Helios in Greek and Roman mythology. ... Hera/Juno, offered the head of Argus by Hermes, places his eyes in the peacocks tail, in a decoration by Jacopo Amigoni (ca 1682 - 1752) There are five figures in Greek mythology named Argus: 1. ...

To free Io, Zeus had Argus slain by Hermes. Hermes, disguised as a shepherd, first put all of Argus's eyes asleep with boring stories. To commemorate her faithful watchman, Hera had the hundred eyes of Argus preserved forever, in a peacock's tail (Ovid I, 625).