Myth of Oneiros

"And Nyx (night) bore hateful Moros (doom) and black Ker (violent death) and Thanatos (death), and she bore Hypnos (sleep) and the tribe of the Oneiroi (dreams). These, then, are the children of Nyx."

Hesiod's Theogony, lines 212-216

"Nestor Appearing in a Dream to Agamemnon" (1805) by Henry Fuseli

In book 2 of Homer's Iliad, Zeus sends a deceptive dream to Agamemnon in the form of Nestor, influencing his decision to lead the Greeks into battle, contributing to events of the Trojan War. The Oneiroi may not be specifically mentioned however, the dream spirit was sent by Zeus.

Homer. "Iliad." Translated by Robert Fagles, Penguin Classics, 1990.

The first mention of the Oneroi in Greek mythology dates back to 8th century BCE in Hesiod's poem "Theogony." Then, in "Metamorphoses," Book XI, Ovid discusses the role of the Oneiroi. Here he describes the entrance to a cave where the Oneiroi (personification of dreams) are said to reside. It emphasizes the ephemeral nature of the dream forms, which are not based on reality but constructed in the realm of imagination. Ovid's "Metamorphoses" explores various aspects of transformation and mythology, and this particular section delves into the world of dreams and the numinous Oneiroi:

"About the cavern's front, whose rocky door

Two massy pine-trees from the centre bore,

There, fil'd a train of forms not real made;

There, empty visions stood, a lifeless shade:

A numerous tribe, not one of which but wore,

In mock'ry features never seen before."

While no comprehensive texts exit on these dream spirits, the Oneiroi are mentioned as well in Pseudo-Apollodorus' "Bibliotheca," Nonnus' "Dionysiaca," Plato's "The Republic," and Virgil's "Aeneid." While these sources leave much to our minds, they do contribute to the broader understanding of the importance of dreams in ancient Greek and Roman culture and literature.