The mother of Darius III who was captured by Alexander was Sisygambis. She was the senior woman of the Persian royal family and was taken prisoner after Alexander defeated Darius at the Battle of Issus in 333 BCE.
Alexander reportedly treated Sisygambis, Darius’s wife, and their children with unusual respect for royal captives. A famous story says Sisygambis mistook Alexander’s close companion Hephaestion for the king because Hephaestion was taller and dressed similarly. Alexander reassured her by saying that Hephaestion was also an Alexander.
Sisygambis later became strongly attached to Alexander, reportedly calling him her son after Darius’s death. She and the royal family remained under protection rather than being publicly humiliated. Ancient accounts say that when Alexander died in 323 BCE, Sisygambis was so overcome with grief that she stopped eating and died soon afterward.
Her parentage is uncertain: ancient and modern accounts variously connect her to the Achaemenid royal family or to a regional Iranian dynasty. That uncertainty does not affect her well-established identity as Darius III’s mother.