New Year's Day is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar used in ancient Rome. With most countries using the Gregorian calendar as their main calendar, New Year's Day is the closest thing to being the world's only truly global public holiday, often celebrated with fireworks at the stroke of midnight as the new year starts. January 1 on the Julian calendar currently corresponds to January 14 on the Gregorian calendar, and it is on that date that followers of some of the Eastern Orthodox churches celebrate the New Year. New Year's Day is a postal holiday in the United States.
The Romans dedicated this day to Janus, the god of gates, doors, and beginnings. After Julius Caesar reformed the calendar in 46 BC and was subsequently murdered, the Roman Senate voted to deify him on the 1st January 42 BC in honor of his life and his institution of the new rationalized calendar. The month originally owes its name to the deity Janus, who had two faces, one looking forward and the other looking backward. This suggests that New Year's celebrations are founded on pagan traditions. Some have suggested this occurred in 153 BC, when it was stipulated that the two annual consuls (after whose names the years were identified) entered into office on that day, though no consensus exists on the matter. Dates in March, coinciding with the spring equinox, or commemorating the Annunciation of Jesus, along with a variety of Christian feast dates were used throughout the Middle Ages, though calendars often continued to display the months in columns running from January to December.
Among the 7th century pagans of Flanders and the Netherlands, it was the custom to exchange gifts at the New Year. This was a pagan custom deplored by Saint Eligius (died 659 or 660), who warned the Flemings and Dutchmen, "(Do not) make vetulas, [little figures of the Old Woman], little deer or iotticos or set tables [for the house-elf, compare Puck] at night or exchange New Year gifts or supply superfluous drinks [another Yule custom]." The quote is from the vita of Eligius written by his companion, Ouen.
Most countries in Western Europe officially adopted January 1 as New Year's Day somewhat before they adopted the Gregorian calendar. In England, the Feast of the Annunciation on March 25, was the first day of the new year until the adoption of the Gregorian calendar in 1752. The March 25 date was known as Annunciation Style; the January 1 date was known as Circumcision Style, because this was the date of the Feast of the Circumcision, considered to be the eighth day of Christ's life, counting from December 25 when his birth is celebrated. This day was christened as the beginning of the New Year by Pope Gregory as he designed the Liturgical Calendar.