At least three known dating systems have been used
The Common Era
This was the standard measurement of time and used CE & BCE standing for Common Era & Before the Common Era, for measuring years with year 1 (CE) being the Year of the Consulship of Caesar and Paullus. The system had no year 0.
The Epsilon Prime Calander
This measurement system was only used during the reign of Epsilon and then by Epsilon themselves. It used the year 2232 CE as the year 0 with APD & BPD which stood for After the Prime Doges & Before the Prime Doges (referring to their "birth" as doges). By 2732 APD the system was abandoned by all but Epsilon.