period was simply named by the consecutive numbers, from
the 11th to the 19th, and the fi nal 9 or 10 days were counted in
reverse order from tenth to the fi rst—the days of the “waning
moon.” Th e fi nal day of a 29-day month, for example, was the
“second waning moon,” while that of a 30-day month was the
“fi rst waning moon.”
Th e fi rst month of the year, Hekatombion, arrived with
the summer solstice (other city-states began the year at dif-
ferent times). Hekatombion was followed by Metageitnion,
Boedromion, Pyanepsion, Maimakterion, Poseidon, Game-
lion, Anthesterion, Elaphebolion, Munychion, Th argelion,
and Skirophorion. Th e intercalary month was known as “sec-
ond Poseidon” and came aft er the month of Poseidon. Th is
calendar results in a year of 354 days, plus the intercalary
month. Th e Athenians fi gured their calendars in eight-year
cycles, with the extra month added in the second, fi ft h, and
eighth years. Th is system was further corrected in 432 b.c.e.
by the astronomer Meton (fl. fi ft h century b.c.e.), who noted
that every 19 years the phase cycles of the moon match the
cycles of the solar years. Meton proposed a 19-year calen-
dar cycle in which there were 235 months; 125 of them were
“complete” 30-day months, and 110 of them were “defi cient”
29-day months. Th e month containing every 64th day be-
came a defi cient month, and that day was omitted; there were
nine intercalary months.
As Greek measurement of the heavens and the sun grew
more precise, astronomers came up with lengthier calendar
cycles. In the fourth century b.c.e. Calippus (ca. 370–ca. 300
b.c.e.) suggested a change to a 76-year cycle, which would
have been a total of one day shorter than the Metonic cycle.
Th e astronomer Hipparchus (ca. 190–ca. 120 b.c.e.) proposed
a 304-year cycle of 3,760 months. Th ese refi nements were
never publicly adopted; they would have meant complex re-
cord keeping and would have made little practical diff erence
to everyday citizens. A second “conciliar” calendar divided
the year into ten prytaneis, marking the term of offi ce of the
prytany, or council chairman, elected from each phylai, or
tribe. (Until 307 b.c.e. there were ten phylai in Athens.)
Th e Athenians and other Greeks named their years ac-
cording to the leader in power (the designation “b.c.e.” not
being in use before the time of Christ). Starting with the Al-
exandrian writers of the third century b.c.e. historians ad-
opted the four-year cycle of Olympiads to date events. Th ey
cited the number of the Olympiad, counting from the fi rst
(in the year we know as 776 b.c.e.), followed by the Olympiad
year—fi rst, second, third, or fourth (“zero” was unknown in
the ancient world). Th e Greeks counted Olympiads to be 49 or
50 months apart, as diff erent city-states inserted intercalary
months at diff erent times.
Th e confusions of the lunar calendar and the intercalary
months prompted Julius Caesar, a leader of Rome, to appeal
to the Alexandrian Sosigenes to come up with an accurate
solar year. Sosigenes, who is mentioned only in the book
Natural History of the Roman writer Pliny the Elder, devised
the Julian calendar, with a year of 12 months and a leap year
including an extra day every four years. Th is calendar has
survived with a slight modifi cation made in 1582 under Pope
Gregory XIII, who suspended the leap day every 400 years to
put the calendar more precisely in line with the solar year of
approximately 365.25 solar days.
Th e ancient Greeks fi rst measured time with the sundial,
which the historian Herodotus (484–ca. 425 b.c.e.) claimed
had originated in Babylonia. A Greek sundial held a verti-
cal gnomon (indicator), which cast the sun’s shadow on a fl at
surface. Later sundials used the inside of a bowl or a circular
depression made in stone or earth. Eleven lines marked out
the hours, with the fi rst hour beginning with the sunrise and
the last ending at sunset. Sundials grew more complex and
precise as diff erent hour lines were marked for diff erent sea-
sons of the year.
According to the biographer Diogenes Laertius, writ-
ing in the third century c.e., the sundial gnomon was the
creation of Anaximander of Miletus (ca. 611–ca. 546 b.c.e.).
Anaximander also fi t the indicator into a simple and portable
wooden instrument made of two pieces of wood set at right
angles. By casting the sun’s shadow on its vertical piece, the
gnomen marked the passage of the sun and the progress of
the day. Th e instrument also held markings showing compass
directions and could predict solstices and equinoxes.
Another instrument used to measure time was the clepsy-
dra (literally “water thief ”), a spherical or cylindrical vessel
made of stone or clay. An aperture at the bottom of the vessel
allowed water to escape at a slow, constant rate and fi ll a re-
ceiving vessel positioned underneath. As the water level rose
in the receiving vessel, the passing hours were indicated by a
series of horizontal lines on its inner surface. Unlike sundials,
clepsydras could be used day or night and on sunny or cloudy
days. Th e best-known example of a Greek water clock is the
Horologion of Andronicus, or Tower of the Winds, built in
the marketplace of Athens in the fi rst century b.c.e. Water
from the nearby Acropolis supplied the Horologion, which
had a 24-hour time indicator as well as sundials to show the
time of day and the seasons of the year.ROME
BY DAVID KELLY
Th e original Roman calendar system, developed in the sev-
enth or early sixth century b.c.e., was based on an agricultural
cycle, not on the lunar cycle; as a result, it had 10 months, for
a total of 304 days. Each new calendar year began in March,
at the vernal equinox. It had 10 months, six with 30 days each
and four with 31 days. Th is is why the Latin names of the
months of our calendar do not correspond to their positions.
Th e ninth month is called September, even though that word
means “seventh” in Latin. In the same way our 10th month
is called October, which to the Romans meant “eighth”;
“November,” the 11th month, translates to “ninth”; and
December, our 12th month, comes from the Roman word for
“tenth.” Aft er December the 61 days remaining in the earth’scalendars and clocks: Rome 171