Quinquenarian calendar

The Quinquenarian calendar (Caphiric Latin: quinquenarius), also known as the Caphiric calendar, is the calendar system traditionally used in the Imperium of Caphiria. Based on the quinary system (base-5), this calendar is structured around units of time in multiples of five, commencing from the traditional year of Caphiria's founding in 480 BC. While the Gregorian calendar is the official civil and ecclesiastical calendar, the Quinquenarian calendar continues to serve significant administrative, cultural, and ceremonial roles within Caphiria. The calendar's evolution spans millennia, with the first documented usage of a base-5 system appearing on ancient patrician burial sites c. 100 BC.

The smallest unit in the Quinquenarian calendar is the quintan, equivalent to a day, while the core unit is a lustrum, a five-year period. Higher divisions of time, such as the quinquennial (25 years), the quinquagenary (50 years), and the pentasculum (250 years), are multiples of a lustrum. A quinnum, equivalent to a year, is divided into five quintimesters (seasons), while a pentade (week) comprises five quintans (days).

Although the Gregorian calendar is prevalent for official and international contexts, the Caphiric calendar's historical resonance and cultural significance are enduring. The calendar traditionally demarcates the reign of each Imperator, adding a further layer of historical and societal relevance to its use. The Quinquenarian calendar is profoundly interwoven into Caphirian societal norms, cultural practices, and spiritual beliefs. From the daily quintan to the epochal pentasculum, each division serves as a rhythmical reminder of life's progression, reflecting natural cycles and embodying Caphirian philosophical values. Major social and historical events are traditionally marked according to the Quinquenarian calendar, underscoring its ongoing cultural significance.

As an example: the current Gregorian date of Friday, September 19, 2031, would be the 3rd Quintan of the 9th Pentade, Autonide, 2nd Quinnum of the 503rd Lustrum in the Quinquenarian calendar. The current Imperator, Constantinus I, began his reign in the 1st Quinnum of the 501st Lustrum (1 January 2025), and has been reigning for 2 full lustrums and is in the 2nd Quinnum of his 3rd Lustrum.Therefore, the current date in the traditional format would be: 3rd Quintan of the 9th Pentade, Autonide, 2nd Quinnum of the 3rd Lustrum of the Reign of Imperator Constantinus I.