Pandrosos or Pandrosus (Ancient Greek: Πάνδροσος) was known in Greek myth as one of the three daughters of Kekrops, the first king of Athens, along with her sisters Aglauros and Herse. The three of them together are often referred to collectively as the Kekropidai after their father.
The name "Pandrosos" carries the meaning of "all dew" or "all bedewed" in the Greek language (drosos, dew). For this reason, Pandrosos is at times called the "Dew Goddess" and the three Kekropidai together are sometimes referred to as the "Dew Sisters."
The name "Herse" also holds connotations of dew in the Greek. This has led to speculation among scholars that originally there were only two Kekropidai and that Herse was a later addition to the myth, functioning essentially as a double of Pandrosos. The purpose of the creation of the character of Herse would have been to bring the number of Kekropidai up to three so as to conform to the common trope of three sisters in Greek mythology (in keeping with the Three Fates, the Three Charites, etc.).
Kekrops is thought to have been born from the soil of Athens itself, and possesses the head and torso of a man and the lower body of a snake. Beyond his status as Athens’ first king, he is known for judging the contest between Poseidon and Athena that decided the naming and patronage of the city. However, following his death, Kekrops is not succeeded by his son, but rather by Erechtheus (also known by the name Erichthonios), the child of Hephaestus and Gaia.
As told by the Bibliotheca, the god Hephaestus, in a fit of passion, attempts to rape the virgin goddess Athena, but is unsuccessful. In vain pursuit, he ejaculates on the Acropolis, and his seed fertilizes the soil there, impregnating Gaia and leading to the birth of Erechtheus. After Erechtheus is born, Athena takes the baby into her care and places him into a chest (or, in some versions of the story, a basket). She entrusts the chest to the Kekropidai, warning them never to look inside.
While Pandrosos faithfully follows Athena’s instructions, Aglauros and Herse are compelled by curiosity to open the chest, provoking Athena's wrath. The two disobedient sisters are driven mad when they see the contents of the chest (in some versions of the myth, they see Erechtheus being guarded by a giant snake; in others, they see Erechtheus himself in the form of a snake), and hurl themselves off of the northern slope of the Acropolis, falling to their deaths. As the dutiful sister, Pandrosos is spared her sisters’ unfortunate fates.