Since humanity left Old Earth, some historical events have had a significant impact on culture and custom across all or some of the Terragen sphere. Lists vary according to one's memetic biases, but these include.

First Order (Terragen sphere)

• Backyarders, 5th century AT
  
• Nanoswarms, 6th century AT
  
• Great Expulsion 622 AT
• First Toposophic (2nd & following toposophics with diminishing direct impact)
• Version War
• Earliest distinct nonhuman or posthuman Terragen cultures (subsequent events are second or third order)

Second Order (Regional)

• Negentropism: First Promulgation of the Precepts, 1965 AT
• Solarism: First Interface, 2014 AT
• NoCoZo: Non-Coercion Agreement 1450 AT
• Sophic League: foundation 4134 AT; roots in the Reformulation of 2752 AT
• Metasoft: founded 22nd century AT, vec takeover 2344 AT, Version Tree 2582 AT
• Keterism: founded at Ain Soph Aur 1788 AT
• Verifex Event: 7434 AT
• Oracle War 10480
• Eta Carina Rush
• Contact with the Muuh, an ancient race with venerable technology
• Contact with the Meistersingers, a race seemingly in contact with several other galactic cultures
• First provolves, and AIs, before they developed their own cultures
• Contact with the To'ul'h (subsequent contacts with lower tech xenosophonts are 3rd order)
• First Interstellar colonies (particularly those founding colonies of their own)

Third Order (niche effects or very local effects)

• Provolution/design of any major clade or a minor exotic clade
• Invention of the Worldhouse
• First Bishop Rings
• Defeat of the Conver Ambi
• Contact with any lower tech xenosophonts (i.e. Paulans)

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