Mesopotamia, one of the earliest civilizations in world history, was located in modern day Iraq. Mesopotamia encompassed the land between the Tigris and Euphrates rivers. The two rivers are fed by numerous tributaries. The entire river system drains from a vast mountainous region of modern day Turkey into to the Persian Gulf.
From the beginning of written history in 3100 B.C. to the fall of Babylon in 539 B.C. indigenous Sumerians, Assyrians, and Babylonians dominated Mesopotamia in a variety of disparate empires and city-states. Lack of natural boundaries and the inability to unite into a single culture led to the early development of state sponsored warfare against each other and foreign invaders.
The earliest historical evidence of state sponsored warfare took place during the Bronze Age. An inscribed stelae found in the ancient Mesopotamian city of Lagash and dated to 2500 B.C. The city state of Lagash and Sumerian city of Umma settled irrigation rights dispute in a battle in which they used wheeled vehicles, warriors in metal helmets, and armed with shields and small lances with bronze spear points.
By the beginning of the Iron age, 1200 B.C., the Assyrians built the largest standing army in the Mediterranean. Their armies had professional soldiers, infantry, charioteers, mounted archers, fast horses, engineers, and wagoners. A unit of royal bodyguards was one of the first regular armies. The Assyrians used iron in their armor, swords, spears, and weapons in Mesopotamia. They developed fast moving chariot formations that dominated Mesopotamian warfare from the 9th to 7th century B.C.