Astyra (Ancient Greek: Ἀστυρα), also known as Astyrum or Astyron (Ἄστυρον), and perhaps also Andeira (Ἀνδειρα), was a small town of ancient Aeolis and of Mysia, in the Plain of Thebe, between Antandrus and Adramyttium. It had a temple of Artemis, of which the Antandrii had the superintendence. Artemis had hence the name of Astyrene or Astirene. There was a lake near Astyra, which communicated with the sea. Pausanias, from his own observations, describes a spring of black water at Astyra; the water was hot. But he places Astyra in the territory of Atarneus. There was, then, either a place in Atarneus called Astyra, with warm springs, or Pausanias has made some mistake; for there is no doubt about the position of the Astyra of Strabo and Pomponius Mela. Astyra was a deserted place, accordin