The New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one. Many cultures celebrate the event in some manner. In the Gregorian calendar, the most widely used calendar system today, New Year occurs on January 1. This was also the first day of the year in the original Julian calendar and the Roman calendar.
New Year's Eve celebration in Copacabana, Rio de Janeiro, Brazil (2004)
Baby New Year 1905 chases old 1904 into the history books in this cartoon by John T. McCutcheon.
A Happy New Year sign in northeastern China
New Year's Eve celebration in Helsinki, Finland (2016)
The Gregorian calendar is the calendar used in most parts of the world. It went into effect in October 1582 following the papal bull Inter gravissimas issued by Pope Gregory XIII, which introduced it as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun.
Christopher Clavius (1538–1612), one of the main authors of the reform
Pope Gregory XIII, portrait by Lavinia Fontana, 16C
First page of the papal bull Inter gravissimas
Detail of the pope's tomb by Camillo Rusconi (completed 1723); Antonio Lilio is genuflecting before the pope, presenting his printed calendar.
