The Curfew of 132 ATC aka Antimatter Removal Act was a diplomatic document signed by Grand Apostle Urban II and Director Gutai. It marked the removal of all antimatter, both industrial and military, from the Galaxy.
The basis of the act was fabricated a month after the detonation of the Ultimatum Bomb, a continent destroying antimatter-based fusion bomb. It was supported by tens of millions of Romans and Heretics and forced the Divine Council and the Oblic Consortium to concur to diplomatic actions.
The violation of the act in 356 ATC marked the collapse of the empire after the climax of Operation Expansion was complete, it lead to over 200 million fatalities in a matter of a week, the largest act of simultaneous genocide by the Heretical Union.