How Long Were Years in Ancient Greece?

How Long Were Years in Ancient Greece?

Ancient Greece, known for its rich history and contributions to civilization, had its own unique way of measuring time. In modern times, we are accustomed to a calendar year consisting of 365 days (366 in a leap year). However, the concept of a year in ancient Greece was quite different.

The Lunar Year

In ancient Greece, the lunar year was commonly used to track time. Unlike the solar year we use today, which is based on the Earth’s orbit around the sun, the lunar year focused on the moon’s phases. A lunar year consisted of 12 months or “moons,” with each month corresponding to one complete cycle of the moon from new moon to new moon.

However, there was a discrepancy between the lunar year and the solar year. The lunar year only accounted for approximately 354 days, which is about 11 days shorter than a solar year. This difference created challenges in aligning the lunar calendar with agricultural cycles and seasonal changes.

The Metonic Cycle

To address this misalignment, ancient Greek astronomers and mathematicians devised a solution known as the Metonic cycle. The Metonic cycle is named after Meton of Athens, who first described it in the 5th century BCE.

The Metonic cycle is based on the observation that after 19 years, the phases of the moon repeat almost exactly on the same calendar dates. This means that every 19 years, there are roughly 235 lunar months or synodic months (the time between two identical phases).

Ancient Greek astronomers used this knowledge to synchronize their lunar calendar with the solar year by periodically adding an intercalary month known as “Embolimos” or “Second Poseideon.” This additional month ensured that the lunar calendar stayed in line with the solar year.

The Athenian Calendar

One of the most well-documented ancient Greek calendars is the Athenian calendar. The Athenian year started with the summer solstice, which fell around mid-June.

This marked the beginning of the month known as “Hekatombaion. “

The Athenian calendar consisted of 12 or 13 months, depending on whether an intercalary month was added. Each month had approximately 29 or 30 days, depending on the lunar cycle. The names of these months were often based on religious festivals or significant events.

A Month in Ancient Greece

In a typical month, ancient Greeks would observe several important dates and events. Let’s take a closer look at an example:

  • Prometheia – A festival honoring Prometheus.
  • Ekdromia – A day dedicated to military training and exercises.
  • Dekate – The tenth day of the month; considered sacred to Apollo and Artemis.
  • Last Quarter Moon – A significant phase of the moon, marking its transition towards a new moon.


In ancient Greece, years were measured using a lunar calendar that consisted of 12 or 13 months based on the phases of the moon. The Metonic cycle was employed to align this lunar calendar with the solar year by adding an intercalary month every 19 years. Understanding how time was measured in ancient Greece provides valuable insights into their culture and way of life.