Each region had its own calendar
Many ancient civilisations had their own calendrical systems. Of
these, the Greek calendar is most likely the most confusing. The Greek
Calendar is much like ancient Greece itself. It shared a certain basic
similarity from region to region, but each city-state kept its own
version.
All the Greek calendars were lunisolar (based on the sun and
moon) and shared the same basic features of the other lunisolar
calendars: twelve months, with a periodic intercalation of a thirteenth.
The Athenian calendar is the best known and most intensively studied.
The Athenian months were named Hekatombion, Metageitnion, Boedromion,
Pyanepsion, Maimakterion, Poseidon, Gamelion, Anthesterion,
Elaphebolion, Munychion, Thargelion, and Skirophorion.
The intercalary
month usually came after Poseidon and was called the second Poseidon.
Hekatombion, and hence the beginning of the year, fell in the summer.
Other Greek regions started their year at different times (e.g., Sparta,
Macedonia in fall, Delos in winter).
For the historian inclined towards tidy orderliness, the regrettable
fact is that the Athenians were simply unwilling to stick to a
completely regular calendar, which makes reconstruction difficult.
Their
irregularity was not from a lack of astronomical knowledge. In 432 BCE,
the Athenian astronomer Meton instituted his 19-year cycle, fixing
regular intercalations (whether Meton got this cycle from Babylonia or
discovered it himself is not known).
From that point, a small group of
Greek astronomers used the Metonic cycle in their calculations, but this
should be regarded as an astronomer’s ideal calendar.
Abundant
epigraphical evidence demonstrates that in the civil calendar, while the
archons inserted approximately the correct number of intercalary months
over the long term, the specific corrections were somewhat arbitrary,
as the archons saw fit. This irregularity doesn’t really affect the
long-term workings of the calendar, but it does make things very
confusing when trying to establish a precise date for an event.
(source polysyllabic.com)
