She asked for the wrong thing, and the result is the most quoted cautionary tale in Greek myth about how to word a request.
Tithonus was a Trojan prince, brother of Priam, and Eos took him. She asked Zeus to make him immortal and he granted it. She had not asked for eternal youth. The Homeric Hymn to Aphrodite tells the story in its cruellest form: while the first grey hairs came he was still lovely, and she cared for him with food and ambrosia; when he was entirely grey she stopped going to his bed; when he could no longer move his limbs at all she shut him in a chamber and closed the shining doors, and there he babbles endlessly, with none of the strength he once had.
Later sources give him a mercy the hymn withholds: he shrinks and dries until he becomes a cicada, chirping in the heat. It is a good image, and it may be an aetiology working backwards from the Greek word for the insect.
Tennyson's dramatic monologue Tithonus, published in 1860, is the definitive modern version — the immortal man at the eastern edge of the world begging to be allowed to die, and the line "the woods decay, the woods decay and fall". Sappho used the story about her own ageing, in a poem recovered from papyrus in 2004, telling her students that her knees no longer carry her and reminding them that Dawn herself once carried off Tithonus and could not keep him young.
The habit of taking men
Tithonus is not the only one. Eos abducts Orion; she abducts Cephalus, husband of Procris, and the consequences of that abduction destroy the marriage in a story Ovid tells at length; she abducts Cleitus. The Odyssey has Calypso complain that the gods resent goddesses who take mortal lovers, and cites Eos and Orion as an example — Artemis shot him for it.
Ancient sources give a reason. Eos, in one account, slept with Ares, and Aphrodite punished her with a permanent and unsatisfiable desire for young men. Whether that is an old tradition or a later explanation for a pattern somebody noticed in the material, it is at least evidence that the pattern was noticed.
The reversal is worth registering. In a mythology where male gods abduct women constantly and the story is told from the god's side, here is a goddess doing the same thing, and the stories are told with sympathy for both parties and with an unusual emphasis on what it costs.
The rosy fingers
She is the most persistent formula in Homer. Rhododaktylos Eos — rosy-fingered Dawn — appears more than twenty times in the Odyssey alone, marking the start of a new day and giving the poem its rhythm. She is also krokopeplos, saffron-robed, and eugeneia, well-born, and she rises from the streams of Ocean to bring light to gods and men.
The formula is a piece of oral-compositional technology, filling a metrical slot, and it is also a genuinely accurate description of a Mediterranean sunrise. Its constant recurrence is one of the things new readers of Homer notice first and one of the things translators argue about most.
Her family is celestial: daughter of the Titans Hyperion and Theia, sister of Helios and Selene. By Astraeus she is the mother of the winds — Zephyrus, Boreas, Notus — and of the stars, including Eosphoros, the morning star. A dawn goddess who mothers the winds and the last star of the night is meteorologically well organised.
Memnon, and the statue that sang
Her son by Tithonus is Memnon, king of the Ethiopians, who came to Troy after Hector's death and was one of the greatest of the Trojan allies. The lost epic Aethiopis told of his fight with Achilles; Zeus weighed the fates of the two men in his scales and Memnon's sank. Eos carried her son's body away and, in one tradition, obtained immortality for him from Zeus. Her tears are the morning dew. The birds called Memnonides were said to rise from his pyre and fight over it annually.
Then the story attached itself to an object. Two colossal seated statues of Amenhotep III stand on the west bank at Luxor, and the northern one — damaged by an earthquake in 27 BCE — began emitting a sound at dawn, most likely from dew evaporating in cracked stone. Greeks and Romans identified it as Memnon greeting his mother, and it became one of the great tourist attractions of the ancient world. Roman visitors, including the emperor Hadrian and the empress Sabina, carved their names and verses on the legs; over a hundred such inscriptions survive. Septimius Severus had it repaired around 199 CE and it has been silent ever since.
That is a mythological narrative attached to a real acoustic phenomenon at a real Egyptian monument, documented by dated graffiti. Few Greek stories leave that kind of trace.
Aurora, and where the lights got their name
The Roman Aurora is a straightforward translation, used heavily in Latin poetry and in every subsequent European allegory of morning. Her most famous image is Guido Reni's ceiling fresco in the Casino dell'Aurora in Rome, painted in 1614, showing her leading Apollo's chariot and scattering flowers — for two centuries one of the most admired paintings in Europe.
The aurora borealis was named by Galileo, or attributed to him, in 1619 — the northern dawn — and the southern counterpart followed. That is her largest surviving presence: the polar lights carry her Roman name in every scientific language.
Otherwise she is a name — a common given name in several languages, a Disney princess, a spacecraft, a Norwegian singer, a great many businesses — and an idea, since the word "aurora" for a new beginning or the start of an age is one of Latin's most successful metaphors.
A dawn goddess with cognates everywhere and cult almost nowhere
Was she worshipped?
Barely, like her siblings. She receives poetic invocation constantly and cult almost never; there are scattered references to altars and to her being honoured alongside other celestial powers, but no significant sanctuary. Greek religion tended not to build for the phenomena themselves, however constantly it described them.
Is she related to any other Indo-European dawn goddess?
This is one of the strongest cases in comparative mythology. Eos, Latin Aurora, Vedic Ushas and Lithuanian Aušrinė all descend from a reconstructed Proto-Indo-European dawn goddess, and the linguistic correspondence of the names is regular rather than approximate. Some of the poetic epithets correspond too — the daughter of the sky, the one who is born again each morning. It is one of the few Greek deities for whom the deep prehistory is reasonably secure.
Which star is Eosphoros?
The morning star, which is the planet Venus. The Greeks originally treated the morning and evening appearances as two objects, Eosphoros and Hesperos, and their identification as one body was credited in antiquity to Pythagoras or Parmenides. Eosphoros is Latinised as Lucifer, "light-bringer", which is how a Greek dawn-goddess's son ended up lending his name, by a long route through a passage in Isaiah about the king of Babylon, to the Christian devil.
Does she appear in art?
Frequently, and she is easy to identify: a winged woman, often in a chariot, often shown pursuing or carrying off a young man — the Cephalus and Tithonus abductions are common vase subjects, with the goddess striding after a fleeing youth. One well-known cup shows her lifting the body of Memnon, a composition that anticipates the Christian pietà by many centuries and is sometimes discussed in that connection.