And, the more interesting question,
“Why was March 25th made New Year’s Day ?”
That question has the same answer as to why do we count the years as AD 2018, 2019, 2020, 2021, 2022, 2023, 2024, etc. ?
In olden days the years were numbered according to a rulers’ reign. For example, the 28th year of the reign of Caesar Augustus, or the 2nd year of the reign of Caesar Nero.
In the sixth century Pope John I asked Dionysius Exiguus [translated into English as “Dennis the Little”] to calculate the dates for Easter in the coming years. Easter is a movable feast and does not fall on the same calendar date each year. So, when Dennis the Little made his calendar charts he explains his new way of numbering the years. He wrote :
“We have been unwilling to connect our cycle with the name of an impious persecutor [Diocletian], but have chosen rather to note the years from the incarnation of our Lord Jesus Christ …”
He had begun his new book with the words :
“anno Domini nostri Jesu Christi DXXXII”
(Latin for “in the year of our Lord Jesus Christ 532,” or A.D. 532).
This is why the current year is counted as AD 2018, that is, 2018 years after the coming of Christ.
Since, Jesus was born on December 25, and counting back nine months before that we can conclude He was conceived, approximately, on March 25th. That is why March 25th was made New Year’s Day by Dennis the Little in the sixth century. This lasted until the adoption of our current calendar. In AD 1752 new Year’s Day was moved to January 1st for England and the American colonies. But, in AD 1751 New Year’s Day was March 25th.
John