The Hyperdrive Calendar, officially the Galactic Standard Calendar, and also known as the Vellae Calendar, the Caladarian Galactic Calendar, or even the Imperial Galactic Calendar, is the official civil calendar and year designation system used in the Caladarian Galaxy. The calendar era used by the system is based around the year of the invention of the modern Hyperdrive, a feat which was first accomplished by the Laurasian Stellar Republic and the Murphian Hegemony in AH 1. All years before this event occurred are designated as Before Hyperdrive (BH); all years after this event are designated as After Hyperdrive (AH). There is no year zero in the Hyperdrive Calendar, so the year AH 1 immediately follows the year 1 BH. The Hyperdrive Calendar era system was devised by the Murphian historia