Well, Happy New Year! I understand that it is slightly belated but I took a week off work (and life) to help celebrate my birthday on the 2nd January. I turned 26, which basically meant that people kept telling me that I was in my late 20s. Whatever.

Why do we have our New Year in January though? In the middle of Winter? What made most of the world decide on this particular calendar?

It was not always like this. The earliest new years celebrations are thought to have happened in Mesopotamia (near where Iraq is now) at around 2000BC, and they celebrated it on the vernal equinox (20th March). The Egyptians celebrated it on the autumnal equinox (20th September).

Well, it was Julius Ceasar. I had no idea about this.

The Roman calendar used to be based off 12 lunar months and there were 355 days in a year. This calendar kept getting out of phase with the seasons, so they would regularly have to stick another month onto the end to get everything lined up again. Keeping the calendar in sync was neglected while civil wars were going on so things got into even more of a mess and Julius Ceasar decided to do something about it.

He asked the astronomer Sosigenes to think of a new calendar that worked. Sosigenes suggested using a calendar that followed the solar cycle, like the Egyptians.
He calculated that this new year would be 365.25 days. It was decided to add a day to February every 4 years to stop the new calendar from falling out of sync. Ceasar added 67 days onto 46BC so that 45BC could start in the 1st January.

He also added days because 45BC was actually meant to start on the Winter solstice but it was not a new moon then. Of course, the new year had to start on a new moon so they postponed it for 7 days. Then 45BC started on the first of January!

January is named after the Roman god Janus, the god of doorways and beginnings. July is named after Julius Ceasar, maybe that astronomer should have gotten a month named after him too?!

However, the year they had calculated was slightly wrong, it was 11 minutes too long! By the mid-15th Century, this had added 10 days to the year and no one really knew when the first of January was. The Roman church was not happy about this so they got round another astronomer, Christopher Clavius, to fix it. He kept the leap years every 4 years but if the year was divisible by 100 it also had to be divisible by 400 to be a leap year. This made the length of a year pretty much completely correct.

This was called the Gregorian calendar, after Pope Gregor XIII who asked for the change. Again, the astronomer got nothing named after him.

Imagine being so powerful that you could just change the calendar. Imagine having a calendar that did not really work! We have come a long way.