Autonoe was one of the fifty daughters born to Danaid and Polyxo. She along with her sisters (and half-sisters) were married to sons of Aigyptos (by his various wives). The night of the mass marriage, she along with forty-eight of her forty-nine sisters and half sisters slew their husbands with knives provided by their own father.
When Autonoe and the other Danaids who had murdered their husbands they were sent to Tartarus and were forced to carry water from the river Styx in a bowls (or jars according to some) with holes over to a tub which leaks at multiple parts. Autonoe and the others were told only when they filled the tub could they wash away their sins. The Danaids continue this essentially impossible task to this very day.
Danaus & Polyxo
Spouse & Lovers
"The twelve sons of a Naias Nymphe named Kaliadne [and Aigyptos]drew lots for the daughters of Polyxo, also a Naias [and Danaus]. The sons were named Eurylochos, Phantes, Peristhenes, Hermos, Dryas, Potamon, Kisseus, Lixos, Imbros, Bromios, Polyktor, and Khthonios; the girls were Autonoe, Theano, Elektra, Kleopatra, Eurydike, Glaukippe, Antheleia, Kleodore, Euippe, Erato, Stygne, and Bryke."
- Pseudo-Apollodorus, Bibliotheca 2. 19 (trans. Aldrich) (Greek mythographer C2nd A.D.)