The history of Arbre is inspired by Earth's history while diverging in some critical areas. It is told throughout Anathem in both the novel and in additional texts, such as the added chronology in the Introduction.
In historical Arbre dates, the year Zero is the year of the Reconstitution. Years before reconstitution are denoted using negative numbers; years after Reconstitution are listed with the suffix A.R., which stands for After Reconstitution.
Pre-Mathic Age[]
-3400 to -3300 Approximate era of Cnoüs and his daughters Deät and Hylaea, largely mythical characters.
-2850 Temple of Orithena founded by Adrakhones.
-2700 Life of Diax.
-2621 Orithena destroyed by volcanic eruption. Beginning of the Peregrin period. Many surviving theors move to the city-state of Ethras.
-2600 to -2300 Golden age of Ethras.
-2415 Birth of Protas, a pupil to Thelenes.
-2396 Execution of Thelenes.
-2335 Death of Protas.
-2272 Ethras forcibly absorbed into Bazian Empire.
-2204 Foundation of the Ark of Baz, a religion.
-2037 Ark of Baz becomes state religion of the Empire.
-1800 Bazian Empire reaches its peak
-1500 Decline of the Bazian Empire. Theors retreat from public life. Saunt Cartas writes Saeculum, starting the Old Mathic Age.
Old Mathic Age[]
-1472 Fall of Baz, burning of its Library. Surviving literates flock to Bazian monasteries or Cartasian maths.
-1150 Rise of the Mystagogues.
-600 Purging of the Mystagogues.
-500 The Rebirth. Dispersal of the mathic system. Theorical advances start the Praxic Age.
Praxic Age[]
-74 The First Harbinger.
-52 The Second Harbinger.
-43 Proc founds The Circle, which (much later) transforms into New Circle.
-38 Proc's work repudiated by Halikaarn.
-12 The Third Harbinger.
-5 The Terrible Events.
0 The Reconstitution. Foundation of the new mathic system. First edition of the Dictionary.