Friday, March 1, 2013

Telling Time in the Renaissance, Part I: A Change in Calendars

Time is a slippery beast. You may believe otherwise, if you live in today’s West. Here, the moments march lockstep in time with the news ticker, Twitter feeds and the stock market bell—every event branded with a number. The precision of industry disguises the artifice that is our experience of time.

In the world of our ancient forbears, however, we had less evidence of time’s passage. The seasons flowed one into another with each year’s refrain, and the phases of the moon signaled the strength of the tides. When those cultures saw fit to measure these intervals, they faced a panoply of decisions in the face of the elements. As civilizations grew, they sometimes saw fit to change those decisions and alter their measure of time. The Renaissance saw at least one such change to fruition.

The calendar of the early Renaissance, the Julian calendar, saw its origins in ancient Rome. It takes its name from Julius Caesar himself, who implemented the new count of years. Rome’s previous calendar, the Calendar of Numa, was a lunar calendar of twelve months. The total count of its days amount to 355 in a year: 10.25 short of a full (tropical) year. To re-align the system with a full orbit of the Sun, some years gained an extra month, which compensated for the missing days of previous years.

In Caesar’s time, the Calendar of Numa fell out of sync with the tropical year. Rome’s political system encouraged officials to insert these ‘leap months’—called intercalary months—at inappropriate times to extend their tenure. Caesar learned of Egypt’s solar calendar during his campaign in Alexandria, and later set to integrate the Egyptian system with the Roman lunar calendar.

The result—the Julian calendar—resembles today’s Gregorian system closely. Caesar added days to the old Roman months to bring the total to 365 per year. The Julian calendar abolished the intercalary month, and instead appended an intercalary day to February in every fourth year. Today, we know these years as leap years. These leap years served to compensate for the quarter-day drift between the 365-day year and the true tropical year.

For over a millennium, the Western world aligned their lives to the passing of the Julian months. But the Julian calendar held a flaw: the tropical year is not 365.25 days in length. It is somewhat shorter, about 265.24219 days. Over time, the seasons drifted across the calendar. By the 16th century, in Pope Gregory XIII’s reign, the seasons arrived ten days out of sync with their assigned dates.

The inaccuracy of the Julian calendar made Catholic life difficult. The Church aligned its festivals with the solstices and equinoxes, echoing Pagan tradition. Solstices and equinoxes are astronomical phenomena, produced by Earth’s axial tilt relative to the Sun at four points in its orbit. The days are longest on the summer solstice, while the winter solstice marks the year’s longest night, and the equinoxes see equal measures of day and night. Since the Julian calendar no longer predicted Earth’s astronomical position accurately, the Catholic Church could not hold Easter, Christmas or other important holidays at the proper time.

When Gregory XIII established the aptly named Gregorian Calendar by Papal bull in 1582, he implemented a few adjustments to the Julian system. The most sophisticated involved the prediction of Easter, but the change with which we are most familiar is the omission of one leap year every century, excepting every fourth century. Most of Italy and much of Europe quickly followed the Pope’s lead, while Protestant countries resisted the change. Nonetheless, many peoples adopted this calendar far and wide over the rest of the millennium—some by choice, some by the sword of European conquest. Today, most of the world lives by Gregorian time.

While the modern calendar took shape in Gregorian times, many differences remain between the keeping of Renaissance time and the keeping of modern time. The common people in Italy measured the day by “Italian hours,” counted from dawn, while astronomers used the Julian date, where the day began at noon. The invention and improvement of mechanical clocks would eventually change these measures. Join me next week, where I delve into these subjects in Part II of “Telling Time in the Renaissance.”


Julian Calendar, Wikipedia 2013.

Gregorian Calendar, Wikipedia 2013.

Roman Calendar, Wikipedia 2013.

Hour, Wikipedia 2013.

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