III.

The Roman Calendar

The original Roman calendar, introduced about the 7th century bc, had 10 months with 304 days in a year that began with March. Two more months, January and February, were added later in the 7th century bc, but because the months were only 29 or 30 days long, an extra month had to be intercalated approximately every second year. The days of the month were designated by the awkward method of counting backward from three dates: the calends, or first of the month; the ides, or middle of the month, falling on the 13th of some months and the 15th of others; and the nones, or 9th day before the ides. The Roman calendar became hopelessly confused when officials to whom the addition of days and months was entrusted abused their authority to prolong their terms of office or to hasten or delay elections.

In 45 bc Julius Caesar, upon the advice of the Greek astronomer Sosigenes (flourished 1st century bc), decided to use a purely solar calendar. This calendar, known as the Julian calendar, fixed the normal year at 365 days, and the leap year, every fourth year, at 366 days. Leap year is so named because the extra day causes any date after February in a leap year to “leap” over one day in the week and to occur two days later in the week than it did in the previous year, rather than just one day later as in a normal year. The Julian calendar also established the order of the months and the days of the week as they exist in present-day calendars. In 44 bc Julius Caesar changed the name of the month Quintilis to Julius (July), after himself. The month Sextilis was renamed Augustus (August) in honor of the Roman emperor Caesar Augustus, who succeeded Julius Caesar. Some authorities maintain that Augustus established the length of the months we use today.