(c. 1,056 B.C.) The (c. 1,392 B.C.) The Middle Assyrian Empire begins, during which Assyria reasserts itself in northern Mesopotamia. succumbs to the pressures of the c. 1,200 B.C. The Bronze Age Collapse, an approximately 300 year period, was a violent, sudden, and culturally disruptive period in which many civiliz... as it begins a period of gradual decline, eventually contracting to control only the main city-state of Assur and its immediate environs.