|Description:|| The failure of the Rule of Man triggered the collapse of most interstellar civilization. While interstellar travel and commerce continued, it was at a greatly reduced rate, and the many worlds of the Imperium turned in on themselves. The period of collapse is termed "Twilight", and it lasted for two and a half centuries.|
Modern historians consider Twilight to have begun in 3693 when the treasury on Hub/Ershur refused to acknowledge a monetary issue of the branch treasury at Antares, which triggered a financial collapse and the destruction of large-scale trade within the Imperium.
The end of Twilight is commonly accepted as the year 3943, when the last governmental body claiming to be the Rule of Man ceased to exist.