Understanding the Origins of One of Africa’s Oldest Calendrical Systems

By Maatii Sabaa

In March 2026, when most of the world marked the beginning of a new year according to the Gregorian calendar, the Oromo people—across Oromia and the global diaspora—celebrated the arrival of a different milestone: the Oromo New Year, 6420. For many outside the Oromo community, this number raises a fundamental question: Where does the year 6420 come from?

The Oromo Calendar: A 2,300-Year-Old Legacy

The Oromo calendar is one of Africa’s oldest indigenous calendrical systems. It is believed to have been developed by the Oromo people around 300 BC . This places its origins at approximately 2,300 years ago—a period when the Oromo were already sophisticated observers of the cosmos.

Known as the Borana calendar or the Dhaha/Henni calendar, it is a lunar-stellar calendar system. This means it relies on astronomical observations—specifically, the phases of the moon in conjunction with the rising and setting of seven particular stars or constellations.

The calendar’s sophistication lies in its integration of astronomy with daily life. It consists of 12 months and 354 days in a year, based on the lunar cycle. It has no weeks, but rather a name for each day of the month. The first day of the Oromo year begins in the month of Bitootessaa (March), when the constellation Triangulum is in conjunction with the new moon.

The Significance of the Number 6420

The year 6420 is reached by counting forward from the calendar’s inception around 300 BC. While the exact starting point is a subject of ongoing scholarly discussion, the calendar’s antiquity is well-established.

For the Oromo people, the calendar is more than just a way to count time—it is a cornerstone of their identity and cultural continuity. As one elder explained at the Walisoo Liiban celebration of the 6420 New Year:

“Observing Birboo at our Galma is not just about marking a calendar. It is about remembering who we are. It is about connecting our past to our future, grounding ourselves in the values of balance, respect for all creation, and community that Waaqeffannaa teaches” .

The calendar is tied to the traditional Oromo religion, Waaqeffannaa, and is used to schedule the Gadaa system of elections and power transfer. The Gadaa system, recognised by UNESCO as an Intangible Cultural Heritage of Humanity, is itself deeply connected to the calendar.

Archaeological and Astronomical Evidence

The Oromo calendar’s origins are not merely a matter of oral tradition. The Namoratunga archaeological site near Lake Turkana, Kenya, has been central to understanding its antiquity. Some scholars have argued that the site, dating to around 300 BC, contains evidence of an early Cushitic calendar that shares astronomical alignments with the Oromo calendar. The site’s basalt pillars are aligned with seven star groups that correspond to the Borana star groups still used in the Oromo calendar today.

However, it should be noted that the relationship between Namoratunga and the Oromo calendar has been debated. Astronomer and archaeologist Clive Ruggles, after re-examining the site, concluded there is no direct relationship. Nevertheless, the broader scholarly consensus acknowledges the calendar’s ancient roots and its continuity into the present day.

A Living Calendar in the Modern World

Today, the Oromo calendar remains a living tradition. In January 2026, Waaqeffannaa faithful gathered at the Galma Amantaa (House of Worship) in Walisoo Liiban, Oromia, to observe the Oromo New Year, Birboo, marking the year 6420. The celebration, which included prayers for peace (nagaa), love (jaalala), and unity (tokkummaa), was described as “a powerful reaffirmation of an ancient identity” and “a community’s declaration of continuity”.

The calendar’s months and day names, with their astronomical origins, are still used by Oromo communities in both Ethiopia and Kenya. The Ayyaantu—Oromo time-experts with knowledge about stars—continue to track time astronomically, preserving a tradition that has survived for millennia.

Conclusion: A Calendar of Identity and Continuity

The Oromo calendar, with its year 6420, is a testament to the ancient astronomical knowledge of the Oromo people and their enduring cultural identity. Its development around 300 BC and its continued use today represent one of the longest continuous calendrical traditions in the world. For the Oromo people, the calendar is not just a way to count years—it is a declaration of continuity, a connection to ancestors, and a guide for the future.

As the Oromo New Year 6420 was celebrated, the message was clear: “May this New Year bring you peace, love, and unity” .

This feature article is dedicated to the custodians of the Oromo calendar and to all those working to preserve and promote Oromo cultural heritage.