This traces the development and evolution of the modern calendar, from the system established by Julius Caesar in 46 B.C. to that of Pope Gregory XIII in 1482.
Just a little more than nine years ago to the day, much of the civilized world anxiously awaited the new year, 2000, and the predicted pandemonium that would ensue when thousands of computers, microchips and technical gadgets would think that the calendar had jumped back to 1900. Many who capitalized on the hysteria profited handsomely, and some still insisted that electronic Armageddon had been narrowly averted. Perhaps many people made New Year’s resolutions not to worry about events over which they had no control. Besides, the world had survived other astronomical anomalies, namely October 15, 1482, which had been preceded, oddly enough, by October 4, 1482.
The leap of 11 calendar days was the culmination of a decade of reform efforts by Pope Gregory XIII, who had been working to correct the calendar established over 1500 years earlier by Julius Caesar. Assisting the pontiff in this formidable task were astronomers Aloysius Lilius and Christopher Clavius. The Gregorian Calendar was immediately adopted by most of the Catholic countries and their colonial possessions, but other nations continued to use their own systems –usually the Julian Calendar- even until the early 20th century. The Eastern Orthodox Church still utilizes the Julian Calendar, which is 13 days ahead of the Gregorian Calendar, for official religious holidays and observances. The Gregorian Calendar most closely follows the solar year, at 365 ¼ days, with every fourth year having an extra day added to the month of February.
The Julian Calendar had evolved from the earlier Roman Calendar, which had ten months and a total of 304 days. Eventually the months of January and February were added, bringing the total days to 355, the approximate length of the lunar calendar. In calculating his calendrical corrections, Julius Caesar enlisted the aid of the Greek astronomer Sosigenes. January 1, 46 BC was the official start of a new era of tracking time, one that would undergo minor tweaking, but remain in place until the late 15th century. Shortly after Julius Caesar’s untimely death in 44 BC, the month of Quintilus –which had originally been the seventh month prior to the addition of January and February- was changed to July to honor the slain dictator. 36 years later, the month of Sextilis –originally the sixth month- was changed to August to commemorate Augustus Caesar, Rome’s first emperor (Kummer: 42). The word “calendar” comes from the Latin “kalends,” meaning the first day of the month.
Adjusting and correcting the calendar has been a centuries-long endeavor that to some extent is still ongoing. Scores of scientists and mathematicians have labored hard to accomplish what is today a nearly-universal system of determining dates. Ancient people first developed calendars based on seasonal events, such as the flooding of major rivers, before turning to the heavens for greater accuracy. Even Pope Gregory’s solution is not perfect, as the months can not be divided into equal lengths, and by the year 4909, his calendar will be off by one day (Snowden, Kummer: 48).
Sources
Snowden, Ben. “The Curious History of the Gregorian Calendar.” Infoplease.® 1 Jan. 2008.
“History of the Calendar.” Infoplease.® 1 Jan. 2008.
Kummer, Patricia K. The Calendar. Franklin Watts, New York: 2005. 29-36, 42-49.
