Prehistory: from the beginning to ca. 4000 B.C. -- First empires: ca. 7000 B.C.-200 A.D. -- The ancient world: ca. 2500 B.C.-900 A.D. -- The Middle Ages: 5th-15th century -- The early modern period: 16th-18th century -- The modern era: 1789-1914 -- The World Wars and interwar period: 1914-1945 -- The contemporary world: 1945 to the present.