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The Terrible Events were a period of world-wide devastation that occurred in the year -5 A.R.. The specific nature of The Terrible Events is not well known as most of the historical record from this period was destroyed. What is known is that high-technology was a major factor, although it is not clear if this was because of an accident at a research facility, a global war, or something else.

It is known that in the centuries following the Terrible Events the climate warmed sufficiently for major population centers to move away from equatorial Eregions. In the novel Erasmas states that "more recently" [1] a decrease in carbon dioxide levels reversed this trend because of a reduction in carbon dioxide in the atmosphere and also to "get away from the solar radiation at the poles."[2] These statement imply both that global warming and the depletion of ozone near the poles became serious issues following the time of the Terrible Events.


The destruction that led to the Terrible Events did not arise suddenly. Serious global upheavals occured in the decades prior to the collapse of the Praxic Age. The Terrible Events were preceded by three major global upheavals known as the three Harbingers. Because of the destruction of records in the Terrible Events specific details are missing.

  • The First Harbinger (A.R. -74) is believed to have been a worldwide outbreak of violent revolutions.
  • The Second Harbinger (A.R. -52) is believed to have been a world war.
  • The Third Harbinger (A.R. -12) is believed to have led to a massive genocide.

Dictionary Entry[]

One of a series of three calamities that engulfed most of Arbre during the last decades of the Praxic Age and later came to be seen as precursors or warnings of the Terrible Events. The precise nature of the Harbingers is difficult to sort out because of destruction of records (many of which were stored on syntactic devices that later ceased functioning) but it is generally agreed that the First Harbinger was a worldwide outbreak of violent revolutions, the Second was a world war, and the Third was a genocide.
The Dictionary, 4th Edition, A.R. 3000

Consequences of the Terrible Events[]

The Terrible Events were the catalysis for the Reconstitution in 0 A.R. which led to the creation of maths and the segregation of science and technology experts from the rest of society. In the time of Erasmas (c. A.R. 3700) it is unclear if this segregation was forced upon the scientific community by the remaining Saecular Power, whether it was voluntary or somewhere between these extremes.

The unrestricted development of high technology was seen as a major reason for the level of destruction in the Terrible Events, in particular with the development of extremely small but powerful weapons of mass destruction like the Everything Killers.

Not all science and technology was restricted following the Reconstitution, and additional restrictions were placed following the three great Sacks.

Dictionary Entry[]

Terrible Events

A worldwide catastrophe, poorly documented, but generally assumed to have been the fault of humans, that terminated the Praxic Age and led immediately to the Reconstitution.

The Dictionary, 4th Edition, A.R. 3000


It seems likely that the increase in global warming and decrease in ozone levels following the Terrible Events were due to the general high level of industrialization and lack of long-term foresight at the end of the Praxic Age. These tendencies are, of course, also present in current real-life civilization.

It is hinted that the Terrible Events were caused by (or occurred shortly after the activation of) very large matter colliders, similar to, but larger than, the Large Hadron Collider.


  1. Anathem by Neal Stephenson, hardcover first edition (2008), p. 300
  2. Anathem by Neal Stephenson, hardcover first edition (2008), p. 300