New Year is the time at which a new calendar year begins and the calendar's year count increments by one. Many cultures celebrate the event in some manner. The New Year of the Gregorian calendar, today mostly in use, falls on 1 January (New Year's Day), as was the case both in the old Roman calendar (at least after about 713 BCE) and in the Julian calendar that succeeded it. The order of months was January to December in the Old Roman calendar during the reign of King Numa Pompilius in about 700 BCE, according to Plutarch and Macrobius, and has been in continuous use since that time. Many countries, such as the Czech Republic, Italy, Spain, the UK, and the United States, mark 1 January as a national holiday.