According to Livy (Livy, Periochae, 47), the consuls first took office on January 1 in 153 BC. The consuls needed to take office early due to a revolt in Hispania. This change became permanent, and so the consular year (which was how the Romans named their years) started on January 1. When the general populace recognized that as New Years isn't clear, nor when the religious year started. Certainly it was accepted by the time C. Julius Caesar reformed the calendar in 46 BC.

The Council of Tours, in AD 567, abolished January 1 as the New Year, but they failed to pick a new date that stuck. So New Year's Day changed depending on country and century. When the Gregorian Calendar was enacted in 1582, they chose January 1, and Catholic countries followed suit. Protestant and Orthodox countries followed their own customs until they converted to Gregorian dates (For Britain and her colonies, New Year's was on March 25th by the Julian calendar until 1752).