Year zero
Year zero does not exist in the anno Domini system usually used to number years in the Gregorian calendar and in its predecessor, the Julian calendar. In this system, the year is followed by . However, there is a year zero in astronomical year numbering (where it coincides with the Julian year ) and in ISO 8601:2004 (where it coincides with the Gregorian year ) as well as in all Buddhist and Hindu calendars.
New Year
March 1 was the first day of the numbered year in the Republic of Venice until its destruction in 1797, and in Russia from 988 until 1492 (Anno Mundi 7000 in the Byzantine calendar). September 1 was used in Russia from 1492 (A.M. 7000) until the adoption of the Anno Domini notation in 1700 via a December 1699 decree of Tsar Peter I.