In a Roman mosaic from antiquity, a man on a street studies the sundial atop a tall column. The sun alerts him to hurry if he does not want to be late for a dinner invitation.
Sundials were ubiquitous in Mediterranean cultures more than 2,000 years ago. They were the clocks of their day, early tools essential to reckoning the passage of time and its relationship to the larger universe.
The mosaic image is an arresting way station in a new exhibition, ”Time and the Cosmos in Greco-Roman Antiquity,” that opened last week in Manhattan at the Institute for the Study of the Ancient World, an affiliate of New York University. It will continue until April.
The image’s message, the curator Alexander Jones explains in the exhibition catalog, is clearly delivered in a Greek inscription, which reads, “The ninth hour has caught up.” Or further translated by him into roughly modern terms, “It’s 3 p.m. already.” That was the regular dinnertime in those days.
Dr. Jones, the institute’s interim director, is a scholar of the history of exact science in antiquity. He further imagined how some foot-dragging skeptics then probably lamented so many sundials everywhere and the loss of simpler ways, when “days were divided just into morning and afternoon and one guessed how much daylight remained by the length of one’s own shadow without giving much thought to punctuality.”
An even more up-to-date version of the scene, he suggested, would show a man or a woman staring at a wristwatch or, even better, a smartphone, while complaining that our culture “has allowed technology and science to impose a rigid framework of time on our lives.”
Jennifer Y. Chi, the institute’s exhibition director, said: “The recurring sight of people checking the time on their cellphones or responding to a beep alerting them to an upcoming event are only a few modern-day reminders of time’s sway over public and private life. Yet while rapidly changing technology gives timekeeping a contemporary cast, its role in organizing our lives owes a great deal to the ancient Greeks and Romans.”
The exhibition features more than 100 objects on loan from international collections, including a dozen or so sundials. One is a rare Greek specimen from the early 3rd century B.C. The large stone instruments typically belonged to public institutions or wealthy landowners.
A few centuries later, portable sundials were introduced. Think of pocket watches coming in as movable timekeepers in place of the grandfather clock in the hall or on the mantel. They were first mentioned in ancient literature as the pendant for traveling. The earliest surviving one is from the first century A.D.
Six of these small sundials are displayed in the exhibition. These were owned and used mostly as prestige objects by those at the upper echelons of society and by the few people who traveled to faraway latitudes.
A bronze sundial in the center of one gallery is marked for use in 30 localities at latitudes ranging from Egypt to Britain. Few people in antiquity were ever likely to travel that widely.
A small sundial found in the tomb of a Roman physician suggested that it was more than a prestige object. The doctor happened to be accompanied with his medical instruments and pills for eye ailment, as seen in a display. Presumably he needed a timekeeper in dispensing doses. He may have also practiced some ancient medical theories in which astrology prescribed certain hours as good or bad for administering meals and medicine.
Apparent time cycles fascinated people at this time. One means of keeping track of these cycles was the parapegma, a stone slab provided with holes to represent the days along with inscriptions or images to interpret them. Each day, a peg was moved from one hole to the next. The appearances and disappearances of constellations in the night sky yielded patterns that served as signs of predictable weather changes in the solar year of 365 or 366 days. Not to mention when conditions are favorable for planting and reaping. Not to mention good or bad luck would follow.
For many people, astrology was probably the most popular outgrowth of advances in ancient timekeeping. Astrology — not to be confused with modern astronomy — emerged out of elements from Babylonian, Egyptian and Greek science and philosophy in the last two centuries B.C. Because the heavens and the earth were thought to be connected in so many ways, the destinies of nations as well as individuals presumably could be read by someone with expertise in the arrangements of the sun, the moon, the known planets and constellations in the zodiac.
Wealthy people often had their complete horoscopes in writing and zodiacal signs portrayed in ornamental gems, especially if they deemed the cosmic configuration at their conception or birth to be auspicious.
It is said that the young Octavian, the later emperor Augustus, visited an astrologer to have his fortune told. He hesitated at first to disclose the time and date of his birth, lest the prediction turn out to be inauspicious. He finally relented.