Wikipedia
Didymeia (flourished 4th and 3rd centuries BC, Greek: η Δηιδάμεια) was a Greek Macedonian noblewoman. She originally came from an upper Macedonian noble family. Didymeia was the daughter of Antiochus and Laodice of Macedonia. Her father served as a military general under King Philip II of Macedon and gained distinction as one of Philip’s officers. Her brother Seleucus I Nicator was one of the Diadochi of Alexander the Great and her paternal uncle was a Greek soldier called Ptolemy.
She had married an unnamed Greek nobleman and had two sons: Nicanor and Nicomedes. Didymeia’s name and the name of her sons were typical Greek names of their time. She may have been the Didymeia that is associated with the mythology of Seleucus I. Her mother’s alleged sexual relations with Apollo to the allegation that the oracle of the Branchidae that greeted her brother as ‘King’ in 312 BC (see Didyma).