British Calendar Change
At the time Cato's Letters were written, England was still using the Julian calendar, and continued to do so until it switched to the Gregorian calendar, which we use today, on December 31, 1751. The Julian date was 11 days behind the Gregorian during this period, and the Julian new year began March 25. So a Julian date of December 31, 1720, would be the Gregorian date January 11, 1721, and the Julian date January 3, 1720, four days later, would be the Gregorian date January 14, 1721. For the convenience of the reader, we are keeping the Julian date in the title, but putting the Gregorian date in square brackets .