In Greek mythology, Pandrosos or Pandrosus (Ancient Greek: Πάνδροσος) was one of the three daughters of Cecrops I, first king of Athens, and Aglaurus daughter of Actaeus. Athena entrusted the Cecropids with the chest holding the infant Erichthonius; in the usual telling Pandrosos alone obeyed and was spared, becoming a model for the Arrephoroi and receiving cult in the Pandroseion beside the Erechtheion.
Adapted from Wikipedia, "Pandrosus" · CC BY-SA 4.0
I.Family
Pandrosos's sisters were Aglauros (Aglaurus) and Herse; together they are the Kekropidai after their father Cecrops. Their brother Erysichthon died without an heir. In one account Pandrosos, rather than Aglauros, is by Hermes the mother of Ceryx.
II.The chest of Erichthonius
After Hephaestus's failed pursuit of Athena, his seed fertilized Gaia on the Acropolis and Erichthonius (Erechtheus) was born. Athena took the infant into her care, placed him in a chest or basket, and entrusted it to the Cecropids with orders never to look inside.
In the common version Pandrosos obeys while Aglauros and Herse open the chest, see the child guarded by (or in the form of) a serpent, go mad, and hurl themselves from the north slope of the Acropolis. Other tellings distribute the blame differently: all three look; Aglauros and Pandrosos are guilty and Herse innocent; or Aglauros alone opens the chest.
III.Cult
The myth was linked to the Arrephoria, a night festival in Skirophorion. Two young Arrephoroi, chosen from aristocratic families, lived on the Acropolis for a year and at the festival carried covered objects — contents unknown even to Athena's priestess — down a secret descent near Aphrodite-in-the-Gardens, left them, and brought something else back. Pandrosos's obedience was the paradigm they were to follow; an old Attic law required that whenever a cow was sacrificed to Athena, a ewe be sacrificed to Pandrosos as well.
The Pandroseion, an open-air sanctuary west of the Erechtheion on the Acropolis's north side, held Athena's sacred olive and an altar of Zeus Herkeios, and connected by doorways to the Erechtheion — a fitting architectural pairing for the myth that binds Pandrosos to the infant's care.