The area was part of several kingdoms of Upper Macedonia, including the ancient Eordaia and Elimiotis, and it was later part of the kingdom of Macedonia. After the Third Macedonian War it was ruled by the Roman Empire. It later became a part of the Byzantine Empire after the breakup into the West and the East. In the early 14th to the 15th century, it was ruled by the Ottoman Empire and lasted until the Balkan Wars of 1913. The Kozani Prefecture was created in 1915 and also included the present Florina, Grevena and the Kastoria regional units.