The University of Western Australia
School of Humanities (Classics and Ancient History)
CLAH 1103 Glory and Grandeur
Notes on Ancient Chronological Systems
In modern Australia, time is measured very accurately. You can tell your age not
merely to the year, but to the hour and perhaps the minute, maybe even the second.
You expect a train to depart or arrive at a time fixed in hours and minutes.
In the ancient world this was not possible. Even years were not always the
same as our own years. Historians need to understand this, and they must be careful
not to make assumptions which are based on the situation which exists in their own
time.
Some dates in ancient history can be calculated very exactly in modern terms
(for instance, if there was an astronomical event which modern astronomers can
time with precision). In other cases, only approximate estimates can be given. For
this reason, students of ancient history often use the abbreviation c. (for the Latin
word circa, meaning ‘about’), when they cannot date an event precisely.
The year
Major units of time have always been measured in the same way by most people:
they have used the length of the solar year, the monthly waxing and waning of the
moon, and the day and the night and their parts. Since the solar year (c. 365 1/4
days) and the lunar month (c. 29 days) cannot be easily reconciled, this is difficult.
The Muslim religious year is an exception, since it is based only on the moon. For
this reason, Muslim festivals take place at different points in the solar year, as one
year follows another.
It has always been extremely important for farmers to measure the seasons
of the year. They need to know when to sow and harvest their crops. Often farmers
would make calculations based on the appearance and disappearance of certain
stars on or from the horizon for this purpose. But man-made calendars were so
unreliable until the time of Julius Caesar, that they regularly got out of step with
these agricultural seasons, and extra (‘intercalary’) months had to be inserted to
bring them back into line with the solar year.
The Egyptians settled on a system of twelve months of 30 days, with five days
added at the end of the year (slightly less than an actual solar year).
Greek practice was (as might be expected because of the multiplicity of
political units), more varied. We have no evidence for the nature of local calendars
in many parts of Greece. Athens is the city whose arrangements are best known.
Here the standard practice became the alternation of ‘full’ months of 30 days with
‘hollow’ months of 29 days. Six of each gave a year of 355 days, and every few years
an extra month was intercalated (i.e., added to the calendar). A similar system,
used occasionally in Greece, was to have twelve lunar months in a year, with an
extra month intercalated every other year. Again, this was only approximately
correct.
In the fifth century B.C. an Athenian astronomer called Meton calculated a
cycle of nineteen years, with regular and intercalated months, which was followed
for several centuries. Again, this Metonic cycle was slightly out of step with the solar
year, and small inaccuracies developed in the course of time.
The Greeks did not have an agreed starting point from which years were
counted. Very long periods of time might be counted in centuries or generations
(thirty years, or three generations to a century). The most common way of denoting
years in Greek cities was by the names of the principal magistrates (a way which
demanded a very good memory when going back more than a few years). Dating by
Olympiads was a late development, and not common. After the time of Alexander
the Great it became more common for individual cities to date events from the time
of their foundation, or refounding, or from notable events such as the Battle of
Actium.
Within each year, Greek cities had various ways of recording the time at
which events took place. Sometimes the month was used as a basis for this. At
Athens, and at some other cities, records often refer to the ‘prytany’. The word
‘prytanis’ means ‘chief, leader’, and at Athens it was customary for committees of
fifty men, chosen from each of the ten tribes, to serve as prytaneis. Each committee
conducted the day-to-day business of the city for one-tenth of the year, and
administrative decisions were recorded as being ‘in the prytany’ of that tribe.
The Greek year sometimes began in spring, or with the new moon following
the summer solstice, or later in summer. Midsummer (in the sense of the longest
day) has always been an important point in measuring time (note the stone circles
at Stonehenge in southern Britain, a monument whose earliest stages were built
before 3,000 B.C.; the major avenue of stones leading into it was aligned to receive
the rays of the rising sun on Midsummer’s Day). The Athenian year began in
midsummer, so for this and for other years which did not begin on January 1
modern scholarly publications often use a double year date, when this can be
established (e.g., 425/4 B.C. indicates the second half of 425 B.C. in our reckining,
and the first half of 424 B.C.).
Because Greek calendars were lunar, and the lunar months did not always
stay in step with the solar year, the day of the month as well as the beginning of the
year could vary from one city to another. The pure ‘lunar’ month could also be out of
step with the ‘civic’ month. This explains the statement of the 4th century BC writer
on musical subjects, Aristoxenus (Harmonic Elements II, 37): ‘The 10th day of the
month for the Corinthians is the 5th for the Athenians and the 8th somewhere else.’
The Roman year originally began in March, at the end of winter. It contained
ten months, ending with December (from decem, ‘ten’), the beginning of winter. The
period until March arrived again seems to have been regarded as useless. Before
500 B.C. the month of January (named after Janus, the god of entrances and
beginnings) had received a name, but it did not actually become the official
beginning of the year until 153 B.C.
In the Roman year March, May, July (called Quintilis because it was the fifth
month until it was renamed in honour of Julius Caesar) and the eighth month,
October, had 31 days, February 28 and the rest had 29. This produced a year of only
355 days, and so from time to time an extra month (not a day, as in our system) was
intercalated after February (i.e. before the beginning of the new year). This was not
always done correctly, and by the middle of the 1st century B.C. the calendar was
three months out of step with the sun.
Julius Caesar therefore reformed the calendar in 45 BC. This new calendar
was so successful that at the time of its reform by Pope Gregory XIII in 1582 it was
only ten days behind (England did not follow suit until 1752, by which time it was
11 days behind). It is now fourteen days behind the Gregorian calendar (this should
not be used as an excuse for late delivery of essays in Roman History units).
From the early Republic onwards, the Romans counted their years according
to the names of the consuls elected at the beginning of each year, as Greek cities had
counted their years by the names of the archons. Lists were kept which could be
consulted when necessary.
Occasionally the Romans calculated dates from the era of Rome, from the
traditional date of the founding of the city, ab urbe condita, ‘from the city founded’.
This date was calculated in slightly different ways by different writers, but 753 B.C.
(in our terms) became the generally accepted date. Dates expressed A.U.C. were
used by some modern scholars, when they were writing about Roman history, until
the early twentieth century.
During the reign of the Roman emperor Diocletian, a system of dating began
to be used which had originally been used in Egypt. This used ‘indictions’, or annual
tax accounting years beginning on September 1st each year. A full indiction cycle
lasted for fifteen years, so we find documents dated to ‘the fifth (or tenth, or
eleventh) year of the indiction (cycle)’. This system began on September 1st A.D.
284, but within a few centuries it had been adjusted forwards a little so that the
indiction year like the consular year began on January 1st.
The Christian Era
According to the calculation of Dionysius Exiguus of Alexandria, made in A.D. 525,
Jesus was born on December 25th in A.U.C. 753 (1 B.C. in the current reckoning).
This calculation was first made as a part of his assigned task of calculating the dates
when Easter would be celebrated in future years. This was rounded off to the
following January 1st, which became the point from which dates A.D. (anno Domini)
were calculated.
In the time of Dionysus it was normal to calculate years in indictions. But
since it was felt that it was wrong to use a system which was associated with a
tyrant who had persecuted the Christians, another means of dating was sought, and
dating in years A.D. gradually became popular.
The evidence for the date of the birth of Jesus is in fact contradictory, and
contains elements which are incompatible. Both Luke (1, 5) and Matthew (2, 1) date
it in the time of King Herod of Judaea, who died in 4 B.C. If there is any truth in the
story of the Massacre of the Innocents, the birth of Jesus should therefore be dated
in the period 7-5 B.C. But other events with which it may be associated are either
difficult to date exactly, or can be dated much later.
In Matthew’s Gospel (Chapter 2) reference is made to a star which guided the
Three Wise Men to Bethlehem. This may have been a comet, or a conjunction of two
stars. Several possible dates have been suggested for such an event. No certainty is
possible here.
Luke (3, 23) says that Jesus was about thirty years old when he began to
preach, and he preached for a year or more before being put to death in the
governorship of Pontius Pilate (A.D. 26-36).
In the Gospel of Luke (2, 1ff.), the birth of Jesus is associated with a census
carried out for the purpose of calculating tax liabilities by the new governor of Syria,
Quirinius (who took office in A.D. 6). There is no record elsewhere of such a census.
If any kind of registration took place at this time, it must have been in A.D. 6 or later.
It is necessary to be careful when calculating the length of periods which run
between B.C. and A.D. dates. The year 1 B.C. (i.e., B(efore) C(hrist) in our current
scheme of dating), was followed by A(nno) D(omini) (‘in the year of the Lord’) 1.
There is no Year 0.
However inaccurate it may be, most of the world, Christian and nonChristian, now calculates years in this way, although some groups, for example
Chinese, Muslims and Thais, also use their own forms of reckoning.
Some non-Christians do not like referring to the Christian era, and prefer to
refer to the Common Era, expressing dates as CE and BCE, i.e., C(ommon) E(ra) and
B(efore) C(ommon) E(ra).
During the Middle Ages calculations were made by Christians about the age
of the world from the time of its creation. These produced various results. Dates are
sometimes expressed in this way in mediaeval texts. More recently, a calculation by
an Irish archbishop made in the 18th century was used as a reference in many texts,
although it is not now taken seriously. Dates expressed in this way are sometimes
preceded by the letter A.M. (anno mundi, ‘in the year of the world’).
The year of the Common Era which we call 2000 could have been expressed as
follows:
AD 2000:
of the reckoning).
Year 4 of the 694th Olympiad (until midsummer, when Year 1
695th Olympiad began).
AUC (ab urbe condita) 2753.
Year 7508 from the Creation of the World (Byzantine
(Archbishop Ussher’s will begin).
calendar.
2000, when year 42 Year A.M. 6004 from the Creation of the World
reckoning).
Year 2543 of the Buddhist Era.
2311 according to the Era of the Seleucid Kings of Syria.
2030 according to the Era of the Battle of Actium.
Year 8 of the indiction cycle (until Sep. 1, when Year 9
Years 1420 and 1421 of the Hijri/Hegira in the Muslim
Year 41 of the Era of the City of Nedlands (until July 1
of the Era of the City began.
Days of the month
Within the month, the Greeks usually marked the days in relation to the new moon
and the full moon. When the way in which the months were fixed was not in step
with the actual state of the moon (because an artificial month of 29 or 30 days was
being used), a month might have two sets of dates, an ‘actual’ new moon and full
moon, and a ‘business’ new moon and full moon; the latter were used for making
payments which were due on these dates.
The Roman month had three points from which days were measured, the
Kalends (Day 1), the Nones (Day 5 or 7) and the Ides (Day 13 or 15). The Ides
probably represent the full moon, and the Nones a day nine days before it.
When the Greeks and the Romans tried to express the interval between two
points in a series, they always counted both the beginning and the end, whereas we
simply subtract. Dates were measured according to the number of days before the
next of these points, counting both the first and the last day (i.e. the Ides of March 44
B.C. fell on the 15th, so in that month the 12th was the 4th day before the Ides).
When Christians say that Jesus was crucified on a Friday and rose from the dead on
the following Sunday, and that this was the ‘third day’, they are preserving this way
of measuring time.
The seven-day week is a Jewish custom (perhaps Babylonian in origin, with a
series of days named after the seven known planets), modified by the Christians,
who made the day of the Sun God, Sunday, rather than Saturday, the Sabbath (this
happened in the time of Constantine the Great, because they wanted to make the
day when Jesus was said to have risen from the dead the day on which religious
ceremonies could be most effectively conducted, and the day of the Sun God had
been made a holy day or holiday). The idea of a regular day when no work was done
was a novel one. In the ancient world in general, there were no regular days of rest
(although religious festivals were frequent, which had much the same effect, so far
as free persons were concerned). Slaves, or course, had no holidays, except for a
Roman festival at the end of the year in December, called the Saturnalia, during
which they were allowed some temporary liberties. The nearest thing to our week
was the Roman cycle of market days (called nundinae, because they came every
eighth day, which by the Roman system of counting was the ninth day).
Hours
To the Greeks and the Romans, hours were inexact (as they are for many people
even today). The only closely fixed points were sunrise, sunset and midday (and in
cloudy weather, even these could not be measured with any exactitude). The most
common practice was to divide each day and each night into twelve ‘hours’. In
summer, the daylight ‘hours’ would be longer and the ‘hours’ of darkness shorter. In
winter the opposite would be true. Hours were counted from daybreak or sunset so
in winter the hours of the day were shorter and the hours of the night were longer,
while in summer the opposite was the case. Thus in midsummer the ‘third hour of
the day’ would begin about 9.00 a.m. in our way of reckoning time, whereas in
winter it would begin rather later. For this reason, if Julius Caesar reports that his
troops conducted a manoeuvre at the second hour of the day, the actual time, in our
terms, must be determined after considering the season of the year at which the
event took place.
Fractions of the hour are sometimes mentioned, but could not be exactly
measured. For this reason, no one in the ancient world could compare the times of
Olympic victors, and ‘records’ could not be made or broken in respect of time.
Clocks
No one in the ancient world had a watch. Some devices for measuring the length of
elapsed time were used - the hourglass, or a water clock (which used a container
with a small exit hole which emptied itself over a certain period). The principal use
of such devices was in the law courts. Clocks, in our sense, are a development of the
Middle Ages.