Ideas: A History of Thought and Invention, from Fire to Freud

by Peter Watson

The calendar we use today is actually a modified version of the one introduced in Rome by Julius Caesar on 1 January 45 BC. The previous year, 46 BC, was 445 days long, to bring it into line, and was known as ‘the last year of confusion’.16 The change was made because, under the previous system, intercalary months, of no determinate length, had been abused by unscrupulous politicians for their own ends–for example, either to lengthen a term of office, or to bring forward an election.17 Caesar abolished both the lunar year and intercalary months and settled on the solar year of 365¼ days, introducing the idea of a leap year every four years to account for this extra quarter day. To begin with, January, March, May, July, September and November all had thirty-one days, the rest thirty, save for February, which had twenty-nine. The changes to the system we have now were introduced in 7 BC by Augustus, who wanted a month (Sextilis) named after him.