Humanity's Coming Dark Age (supporting details)

A short list of empire collapses:

• 2200-2170 BC
  • Egypt--First Intermediate Period (also affected whole of Eastern Mediterranean and Middle East)
• 1700-1650 BC
  • Egypt--Second Intermediate Period
• 1100-1050 BC
  • Egypt--Third Intermediate Period (also affected whole of Eastern Mediterranean and Middle East)
• 1500-1450 BC
  • Asia Minor--Hittite dark age after death of King Telepinus
• 1100-800 BC
  • Greece--between collapse of Mycenaean civilisation and rise of classical city states
• 500-400 BC
  • Italy--Italic Middle Ages; Etruscan decline also affecting Phoenicians and Greeks
• 720-200 BC
  • China--Spring-Autumn and Warring States Periods
• AD 400-600
  • Britain--between the departure of the Roman legions and the arrival of St Augustine
• AD 220-280
  • China--First Partition
• AD 480-580
  • China--Second Partition
• AD 910-960
  • China--Third Partition
• AD 1000-1200
  • Peru--between collapse of Huari-Tiahuanaco and foundation of Chimu empire
• AD 750-950
  • Valley of Mexico--turmoil following collapse of Teotihuacan
• AD 400-700
  • Southeastern US--between collapse of Hopewell culture and rise of Mississippian