Instruments for measuring and managing time could be seen practically everywhere in the Greek and Roman world — more than 500 Greco-Roman sundials, for example, have been found throughout the Mediterranean world and as far as Afghanistan. Public institutions and wealthy individuals owned sundials, water clocks, and calendar inscriptions, and there were also ingenious portable sundials and mass-produced calendar boards for common households. Religious, civic, and private activities were organized around time-telling practices grounded in astronomy. The sun’s risings and settings, the moon’s phases, and the seasonal progressions of the sun northward and southward gave rise to the days, months, and years out of which calendars were constructed. For many purposes, vague divisions of the day, such as “late afternoon,” were adequate; but the Greeks adopted the Egyptian division of daytime (from sunrise to sunset) and nighttime (from sunset to sunrise) into twelve hours each, designing sundials and mechanical clocks that ensured all the hours of daytime, and all those of nighttime, were equal in duration. Under the Roman Empire, the technology of reckoning time was further developed and popularized to an extent unparalleled in any other ancient civilization.

Time and Cosmos in Greco-Roman Antiquity displays an unprecedented range of objects representing both the tools used to measure time — a field in which Greek scientific ingenuity was revealed to the broader public — and the ways in which the roles of time in the natural, spiritual, and personal worlds were visualized. The center of the first gallery is devoted to a selection of sundials and water clocks that illustrate the variety and virtuosity of their designs. Surrounding them are examples of time-related imagery focusing on the motifs of the sundial, the celestial sphere, and the zodiac. Time was inextricably linked in Greco-Roman thought with a geocentric conception of the cosmos as an immense celestial sphere enclosing and spinning around the terrestrial globe. In Greco-Roman art, the sundial and the sphere were visual emblems of time as well as its cosmic associations, subtly reminding the user of his or her mortality but also evoking intellect and wisdom. The zodiac — the twelve constellations through which the sun, moon, and planets made their revolutions — was yet another image for cyclic time and renewal. Additional objects on view in this gallery relate to the highly popular astrological practice of forecasting people’s lives through horoscopes, which claimed to bring time, the heavens, and human destiny into the closest imaginable connection. Lastly, an assemblage of Roman coins shows how emperors from Augustus onward exploited astrological symbolism and images of time to confirm their authority and the cosmic regeneration supposedly marked by each new reign.

In the second gallery, a series of inscriptions illuminates the functions of calendars in Greek and Roman society and the use of pegboards (parapegmas) for forecasting weather as well as auspicious and inauspicious days. The remarkably varied assembly of portable sundials, some presented with reference to their archaeological context, anticipates the double role of modern watches as articles of both status and utility. A unique portable sundial with calendrical gear work leads thematically to the most astonishing and complex ancient representation of time and cosmos, the Antikythera Mechanism.