people put them in larger containers of water and they grad-
ually fi lled and sank.
One of the earliest water clocks discovered in Asia was
bronze basin water clock dating to the Han Dynasty (202
b.c.e.–220 c.e.). It contained several wooden arrows carved
with lines; as water fl owed out of the basin, the arrows sank,
allowing the viewer to tell how much time had passed by
markings on the arrows. Starting around 300 c.e. Chinese
artisans began making more elaborate and accurate water
clocks, using multiple basins to hold water and fl oating ar-
rows. Some of these clocks could ring bells to mark the hours.
Others were attached to astronomical devices that showed
the positions of the stars and planets.
EUROPE
BY AMY HACKNEY BLACKWELL
Th e earliest European systems of keeping time were based on
the movements of the sun and the moon. Stone Age people
as early as 30,000 years ago appear to have kept track of days
by making notches in bones. Rituals were timed according to
the phases of the moon, and the new moon was a common
time for celebrations. People observed the natural changes
that happened to plants and animals at particular times and
remembered them from year to year. Some ancient people
probably named the times of the year according to events
that took place in particular seasons, such as “deer time,” or
“bird-migration time.”
In prehistoric times people built megalithic, or large
stone, structures in western and northern Europe, some of
which may have functioned as primitive solar calendars. One
of the most famous such sites is Newgrange in Ireland, a tomb
that was built in about 3200 b.c.e. Newgrange consists of a
passageway leading to a subterranean burial chamber con-
taining several side chambers. Th e entrance to the tomb is
constructed so that every year at the winter solstice the rising
sun shines through a slit over the entrance and illuminates
the main burial chamber for 17 minutes. When Newgrange
was built, the light would have fallen directly onto a spiral
design on the far wall.
Other Stone Age sites in Ireland were also designed to
catch the sun on particular days of the year. Th e tomb at
Dowth catches the light of the setting sun at the winter sol-
stice. Th e tomb at Knowth has an eastern-facing passage that
catches the light of the rising sun on the spring and autumn
equinoxes, the two days each year when day and night are
of equal length. Knowth’s western-facing passage catches the
light of the setting sun on the same days. Stonehenge, a circle
of giant stones built in England between 2700 and 1500 b.c.e.,
also appears to have been constructed to catch sunlight on
specifi c days. Sunlight shines on the center of the monument
on the day of the summer solstice, and similar phenomena
happen at the equinoxes.
Ancient people kept track of the seasons for various rea-
sons but mostly to know when to plant or harvest their crops.
Th e Celtic and Germanic people who lived in Europe in an-
cient times also used calendars to help them plant and reap,
but they appear to have been more interested in keeping track
of days for ritual purposes. Holidays fell on the winter and
summer solstices and the spring and autumn equinoxes, and
ancient European calendars were designed to identify these
days. Druids, the priests of the Celtic world, used calendars to
plan festivals—one in each quarter of the year. Because each
festival fell on either an equinox or a solstice, they needed to
know when these days would occur. Some scholars believe
that Celts began using calendars as early as 800 b.c.e. Th e
most famous Celtic calendar is the fi rst century c.e. Coligny
calendar, found in France in 1897 and dated to the fi rst cen-
tury c.e. Th e calendar’s letters and numbers were carved in
Latin letters on a bronze tablet. Th e tablet depicts a fi ve-year
cycle that contains exactly 62 months.
Th e Coligny calendar, a similar calendar found nearby
at Villard d’Heria, and the writings of the Romans Julius
Caesar and Pliny the Elder have provided historians with
the means of reconstructing the Celtic calendar system. Th e
Celtic calendar was lunisolar, which means that it tracked
the movements of both the earth around the sun and the
moon around the earth. Julius Caesar (100–44 b.c.e.) noted
that the Gauls kept track of time by counting nights, not
days. Th e Celtic calendar based its months on the cycles of
the moon, though no one knows whether months began at
the new moon or the full moon. Each month was divided
into two halves, or fortnights; the fi rst half was 15 days, and
the second half was 14 or 15 days, alternating by month.
Th e 30-day months were considered lucky, and the 29-day
months were thought to be unlucky. Th e lunar year was 354
or 355 days long. To keep the year in sync with the earth’s
orbit around the sun, or the solar year, Celts added a 13th
month every two and a half years. Scholars believe that each
new year began on the autumn equinox.
As the Romans gained power, they spread their calendars
through Europe. Before 46 b.c.e., people in Spain and other
parts of Europe under Roman domination used the old Ro-
man calendar. Th is calendar had 12 lunar months, adding up
to 355 days in a year; the Roman priests would periodically
insert an extra month between February and March to put
the calendar back in line with the seasons. Th e decision of
whether to add the extra month was entirely up to the discre-
tion of the priest in charge, and some priests did not bother
to add the month for several years in a row. Th e calendar be-
came quite confusing, especially for people who lived some
distance from Rome, and most people using the system never
knew what date it was.
Th e Gauls and Germans gradually adopted the Julian
system created by Julius Caesar in 46 b.c.e. Under this calen-
dar, a year was 365 days long, with an extra day added to Feb-
ruary every four years. Th e year was divided into 12 months,
and each week consisted of seven days, with both months and
days named aft er gods. Th e Julian system was virtually iden-
tical to the modern Gregorian calendar. Th e Germans andcalendars and clocks: Europe 169