Prio Diciny (abbreviated P.D. or PD) is a designation used within the Oloun calendar to denote the previous historical era. The calendar era to which it refers is believed to be based upon the deliverance of Humanity from its apocryphal ancestral home, Sol System. Events Prio Diciny denote those that occurred previous to this exodus, those notated Ono Diciny (On.D.) occurred after.