Sterope (Ancient Greek Στερόπη, "lightning") was a princess of Iolcus, daughter of King Acastus by Astydamia or Hippolyte. In Apollodorus she appears only inside Astydamia's false message to Peleus' wife Antigone, claiming that Peleus meant to cast Antigone aside and marry Sterope instead — a lie that helps destroy the marriage and drive Peleus into exile.
Adapted from Wikipedia, "Sterope" · CC BY-SA 4.0
I.The false bride
Apollodorus (Bibliotheca 3.13.3) names Sterope only in Astydamia's intrigue against Peleus. After Peleus rejects Astydamia's advances, she writes to Antigone that Peleus intends to marry Sterope; Antigone hangs herself, and Peleus later takes revenge on Acastus' house.
Sterope herself has no independent episode beyond that calumny — a narrative instrument in the Peleus–Acastus feud.
II.Homonyms
This node (sterope-acastus) is Acastus' daughter only. She is not Sterope the Pleiad (sterope-pleiad), nor Steropes the Cyclops (steropes-cyclops), nor the Pleuronian, Calydonian, Tegean, or Helian Steropes listed on the Wikipedia disambiguation.