The Median Empire, was the first Iranian dynasty corresponding to the northeastern section of present-day Iran, Northern-Khvarvarana and Asuristan (now days known as Iraq), and South and Eastern Anatolia. The inhabitants, who were known as Medes, and their neighbors, the Persians, spoke Median languages that were closely related to Aryan (Old Persian). Historians know very little about the Iranian culture under the Median dynasty, except that Zoroastrianism as well as a polytheistic religion was practiced, and a priestly caste called the Magi existed. Traditionally, the creator of the Median kingdom was one Deioces, who, according to Herodotus, reigned from 728 to 675 BCE and founded the Median capital Ecbatana (Hâgmatâna or modern Hamadan). Attempts have been made to associate Daiaukku, a local Zagros king mentioned in a cuneiform text as one of the captives deported to Assyria by Sargon II in 714 BCE, with the Deioces of Herodotus, but such an association is highly unlikely. To judge from the Assyrian sources, no Median kingdom such as Herodotus describes for the reign of Deioces existed in the early 7th century BCE; at best, he is reporting a Median legend of the founding of their kingdom. According to Herodotus (History of Herodotus), Deioces was succeeded by his son Phraortes (675-653 BCE), who subjugated the Persians and lost his life in a premature attack against the Assyrians. Some of this tale may be true. Assyrian texts speak of a Kashtariti as the leader of a conglomerate group of Medes, Scythians, Mannaeans, and miscellaneous other local Zagros peoples that seriously threatened the peace of Assyria's eastern borderlands during the reign of Esarhaddon (680-669 BCE). It is possible that Phraortes is this Kashtariti, though the suggestion cannot be proved either historically or linguistically. That a Median king in this period exerted political and military control over the Persians is entirely reasonable, though it cannot be proved. Beginning as early as the 9th century, and with increasing impact in the late 8th and early 7th centuries, groups of nomadic warriors entered western Iran, probably from across the Caucasus. Dominant among these groups were the Scythians, and their entrance into the affairs of the western plateau during the 7th century may perhaps mark one of the important turning points in Iron Age history. Herodotus speaks in some detail of a period of Scythian domination, the so-called Scythian interregnum in Median dynasty history. His dating of this event remains uncertain, but traditionally it is seen as falling between the reigns of Phraortes and Cyaxares and as covering the years 653 to 625 BCE. Whether such an interregnum ever actually occurred and, if it did, whether it should not be dated later than this are open questions. What is clear is that, by the mid-7th century BCE, there were a great many Scythians in western Iran, that they, along with the Medes and other groups, posed a serious threat to Assyria, and that their appearance threw previous power alignments quite out of balance. Herodotus reports how, under Cyaxares of Media (625-585 BCE), the Scythians were overthrown when their kings were induced at a supper party to get so drunk that they were then easily slain. It is more likely that about this time either the Scythians withdrew voluntarily from western Iran and went off to plunder elsewhere or they were simply absorbed into a rapidly developing confederation under Median hegemony. Cyaxares is a fully historical figure who appears in the cuneiform sources as Uvakhshatra. Herodotus speaks of how Cyaxares reorganized the Median army into units built around specialized armaments: spearmen, bowmen, and cavalry. The unified and reorganized Medes were a match for the Assyrians.

They attacked one of the important Assyrian border cities, Arrapkha, in 615 BCE, surrounded Nineveh in 614 BCE but were unable to capture it, and instead successfully stormed the Assyrian religious capital, Ashur. An alliance between Babylon and the Medes was sealed by the betrothal of Cyaxares' granddaughter to Nabopolassar's son, Nebuchadrezzar II (605-562 BCE). In 612 BCE the attack on Nineveh was renewed, and the city fell in late August (the Babylonians arrived rather too late to participate fully in the battle). The Babylonians and the Medes together pursued the fleeing Assyrians westward into Syria. Assyrian appeals to Egypt for help came to nought, and the last Assyrian ruler, Ashur-uballit II, disappeared from history in 609 BCE. The problem, of course, was how to divide the spoils among the victors. The Tehran (National Museum) cuneiform sources are comparatively silent, but it would seem that the Babylonians fell heir to all of the Assyrian holdings within the fertile crescent, while their allies took over all of the highland areas. The Medes gained control over the lands in eastern Anatolia that had once been part of Urartu and eventually became embroiled in war with the Lydians, the dominant political power in western Asia Minor. In 585 BCE, probably through the mediation of the Babylonians, peace was established between Media and Lydia, and the Halys (Kizil) River was fixed as the boundary between the two kingdoms. Thus a new balance of power was established in the Middle East among Medes, Lydians, Babylonians, and, far to the south, Egyptians. At his death, Cyaxares controlled vast territories: all of Anatolia to the Halys, the whole of western Iran eastward, perhaps as far as the area of modern Tehran, and all of south-western Iran, including Fars. Whether it is appropriate to call these holdings a kingdom is debatable; one suspects that authority over the various peoples, Iranian and non-Iranian, who occupied these territories was exerted in the form of a confederation such as is implied by the ancient Iranian royal title, king of kings. Astyages followed his father, Cyaxares, on the Median throne (585-550 BCE). Comparatively little is known of his reign. All was not well with the alliance with Babylon, and there is some evidence to suggest that Babylonia may have feared Median power. The latter, however, was soon in no position to threaten others, for Astyages was himself under attack. Indeed, Astyages and the Medians were soon overthrown by the rise to power in the Iranian world of Cyrus II the Great.