John Malalas
John Malalas tells us Seleucus had a sister called Didymeia, who had sons called Nicanor and Nicomedes. It is most likely the sons are fictitious. Didymeia might refer to the oracle of Apollo in Didyma near Miletus. It has also been suggested that Ptolemy (son of Seleucus) was actually the uncle of Seleucus.