In England during the Middle Ages 25 December was taken as the start of the year. In the late 12th century the start of the year was shifted by nine months to 25 March. The official start of the year only became the familiar 1 January in 1752, the year in which England adopted the Gregorian Calendar.
The first month of the year January is named after Janus the two-faced Roman deity for beginnings and transitions. Courtesy Wikimedia Commons