Zoroaster came unharmed out of the fire, and bade them offer sacrifice for the god had visited the place. After this Zoroaster did not associate with all men, but only with those who were most adapted to receive the truth and converse with the god, whom the Persians called Magians, _i.e._ those who have skill to serve the Divine Being.[125] Kephalion asserted that Zoroaster the Magian, the king of the Bactrians, fought with Semiramis and was vanquished by her.[126] Theon of Alexandria also speaks of the conflict between Semiramis and the Bactrian Zoroaster. Arnobius is aware of the battle of Ninus with Zoroaster and the Bactrians,[127] and in Eusebius Zoroaster, the Magian, the king of the Bactrians, fights against Ninus.[128] According to the treatise of Eubulus of Athens on Mithras, Porphyrius related that Zoroaster had consecrated a natural cave, in which were flowers and springs, in the neighbouring mountains of Persia, in honour of Mithra, the creator and father of all, and since that time the favour of the god had been sought in a cave.[129] Ammianus Marcellinus calls Zoroaster a Bactrian, and tells us that Hystaspes, the father of Darius, spread abroad the doctrine of the Magians.[130] Agathias remarks that the Persians of his time asserted that Zoroaster, or Zaradus, as they called him, who gave them their religious doctrine and law, the son of Oromasdes, lived at the time of Hystaspes; but they made the assertion in such a manner that no man knew whether this Hystaspes was the father of Darius or some other of the name. But whatever the date of his life, he changed the earlier forms of worship, and was the discoverer of the doctrine of the Magians.[131] Suidas distinguishes between the Perso-Mede Zoroaster, the chief of the Magians, and the astronomer of the same name, an Assyrian, who lived at the time of Ninus.[132] In Syncellus, Zoroaster is the first of the eight Median kings, who, according to the statement of Berosus, reigned over Babylonia from 2458 to 2224 B.C.[133]