Jason of Pherae (‹See Tfd›Greek: Ἰάσων ὁ Φεραῖος) was the ruler of Thessaly during the period just before Philip II of Macedon came to power. He had succeeded Lycophron I of Pherae, possibly his father, as tyrant of Pherae and was appointed tagus, or chief magistrate, of Thessaly in the 370s BC and soon extended his control to much of the surrounding region. Controlling a highly trained mercenary force as well as the famous Thessalian cavalry, Jason briefly transformed Thessaly into a powerful Greek state and even spoke of invading the Persian Empire.