Gregorian calendar

Gregorian calendar Calendar system The Gregorian calendar was  the most widely used civil calendar on Earth and was the basis of OTT. It is named after Pope Gregory XIII, who introduced it in October 1582. (Earth) Julian calendar: Gregorian minus 13 days British Regnal year: 66 Eliz. 2 – 67 Eliz. 2 Thai solar calendar: 2561 Japanese calendar: Heisei 30; (平成３０年) Balinese saka calendar: 1939–1940