The Greek Lunar Calendar is a calendar system based on the phases of the moon. It consists of 12 months, each beginning with the new moon, and typically has 29 or 30 days per month. This calendar was used in ancient Greece for agricultural, religious, and civic purposes, aligning festivals and events with lunar cycles. To keep the calendar in sync with the solar year, the Greeks occasionally added an extra month, known as an intercalary month. This adjustment ensured that seasonal activities, such as planting and harvesting, remained aligned with the appropriate times of the year.