In this volume you will learn about four major Mesopotamian civilizations.The first was Sumer, which began about 3300 BC. The Sumerians contributed to the development of the calendar, metalworking, the wheeled cart, and the potter's wheel. They also created the classic Epic of Gilgamesh.The second great empire you'll learn about is Babylonia. The Babylonians added to the knowledge of astronomy, mathematics, and law. In about 1400 BC the Assyrians of the north freed themselves from Babylon's control. Fierce and warlike, they were the first to use horses as cavalry. They built roads and organized a mail service for communication. Despite their ferocity, their art and architecture were magnificent. The Assyrians also preserved cuneiform texts in great libraries.