At the beginning of the 6^th century B.C. the Medes and the Babylonians waged one of the greatest wars of ancient history to put an end to the cruel tyrannical rule of the Assyrians in the Near East. As the last great Assyrian king, Ashurbanipal, destroyed Elam, the Babylonians had to resort to the Medes in order to escape capitulation to the Assyrians. As for the Medes, they had long mulled the idea of annihilating the Assyrians; long before their pact with the Babylonians, they conquered the city of Assyria, the ancient capital of the Assyrian empire, in 614 B.C. It was in the ruins of Assyria where the Medes king Cyaxares and the Babylonian king Nabopolassar entered into a pact to unite in the battle against the Assyrian king and conquer other cities. In the midst of the years 609-614 B.C. the Assyrian empire collapsed and their land was subjugated by the Medes and the Babylonians. This alliance, however, proved to be short-lived and after the loot of Assyria the Medes-Babylonians relations deteriorated and a Medes invasion of Babylon was much expected. However, before the Medes and the Babylonians could muster their might in a battle against each other, the Persian under Cyrus the Great subjugated the Medes and Babylonians and other territories to the east. The current article seeks to put the Medes-Babylonians pact in its proper context and study the fall of the Assyrian empire and analyze the relations between the Medes and the Babylonians in the wake of the Assyrian fall until the rise of Cyrus the Great (530-559 B.C.)