Astronomy Civilisations Historic Accomplishments History Learn Science

The Borana Calendar and How it works (Existing from 300 BC until Today)

Many non-Africans sometimes wonder, “Did Africa invent anything?” The unambiguous answer is yes: a lot of things. One of these inventions was a calendar system by Borana people of Ethiopia at a date as old as when Greece invented the Athenian calendar (an ancient calendar also known as the Attic Calendar). Unlike the Athenian calendar, the Borana calendar has survived 2,300 years.

Amongst the Oromo people, the people of the Borana grouping are oldest members of the much larger group (Oromo). The other groups that make up the Oromo people are the Arsi and the Guji tribe. The people of the Borana grouping are situated within the southern part of Ethiopia and the Northern part of Kenya (within the border), and also some parts of Somalia.

They are known as ‘Cushitic’ people, which means they are under a branch of the Afroasiatic language family, and they live in the east region of Africa. The Oromo culture may be referred to as “Galla” in some works of literature, but they are most popularly known as Oromo.

They speak the language Oromiffa, and their religion ranges from traditional worshiping to Islam and Christianity. The traditional name for God is Waqa, and saint-like divinities are called Ayanas.

The Borana Oromo calendrical system has been in existence since 300 BC and relies on astronomical observations of the moon and stars. The lunar-stellar calendrical system does not use solar (sun) observation at all, as the area is situated close to the equator. This means that there is little or no change in the behavior of the sun throughout the year.

Dr. A Legesse was the first person to discover that the Borana people used a unique calendrical system in the early 1970s.

How The Borana Oromo Calendar Works

A year under the Borana calendar is made of 354 days making it 10 – 11 days shorter than the solar one. Twelve synodic months make up a year, and each month is made up of 29.5 days. The calendar uses the conjunction of seven stars (Beta Triangulum, Pleiades, Aldebaran, Bellatrix, Central Orion, Saiph, and Sirius) in different lunar phases to determine the days.

Ayantu is the name given to the timekeepers of the tribe who watch the phase of the moon and determine the days and beginning of each month. The months are identified by the ayantu who notice a unique astronomical development that occurs once a year. The length of the month is measured by the time the moon takes to go through all the phases completely.

The Borana Calendar does not offer weeks but each day has a name. There are only 27 names available, so for the 28th, 29th, and or 30th day, the name is recycled, and the first two or three names are used for the last two or three days. This means that each month starts with a different name and there is no fixed name for a day. The Borana Ayantu will determine if the month will run into 29 or 30 days based on astronomical observations. The days begin and end with the rising and setting of the sun.

The Borana names of 27 days include: Bita Kara, Bita Lama, Sorsa, Algajima, Arb, Walla, Basa Dura, Basa Ballo, Carra, Maganatti Jara, Maganatti Briti, Salban Dura, Salban Balla, Salban Dullacha, Gardaduma, Sonsa, Rurruma, Lumasa, Gidada, Ruda, Areri Dura, Areri Ballo, Adula Dura, Adula Ballo, Garba Dura, Garba Balla, and Garba Dullacha.

The Borana names of months include:

  • Bittottessa (Triangulum)
  • Camsa (Pleiades)
  • Bufa (Aldebaran)
  • Wacabajjii (Bellatrix)
  • Obora Gudda (Central Orion – Saiph)
  • Obora Dikka (Sirius)
  • Birra (Full moon)
  • Cikawa (gibbous moon)
  • Sadassa (quarter moon)
  • Abrasa (large crescent)
  • Ammaji (medium crescent)
  • Gurrandala (small crescent)

The Different Stars Used To Derive The Calendar

There are seven stars tracked at different phases and used by the Borana Ayantu to derive the calendar. They are:

  • Beta Triangulum (1)
  • Pleiades (2)
  • Aldebaran (3)
  • Bellatrix (4)
  • Central Orion (Orion Sword and Belt) (5)
  • Saiph (6)
  • Sirius (7)

The conjunction of the new moon with the Beta Triangulum signifies the beginning of a new year. This is one of the most important astronomical observations made by the ayantu. This new year day is called Bittottessa. After this, the next month is determined when a new moon appears in conjunction (“setting with” or “rising with”) with the Pleiades, and it continues that way.

The third month will be determined when the Aldebaran is in conjunction with the new moon. The fourth month begins when Bellatrix is side by side with the new moon. The fifth month begins when the new moon is in conjunction with the area between Central Orion and Saiph, so on and so forth.

The Borana Ayantu derives the first six months of the year using astronomical observations of the seven stars within six specific locations in conjunction with the appearance of the new moon. The last six months are determined using the phases of the moon from full moon to small crescent. These phases are determined using the moon in conjunction with the position of the Beta Triangulum.

The Borana year starts afresh again when a new phase moon is seen side by side with the Beta Triangulum, and that’s how the whole calendrical system is determined using astronomical observations.

The Relationship Between The Namoratunga And The Borana Calendar

In 1977, the Namoratunga, an ancient astronomical observation site of the Borana people located in Kenya, already known to the Borana people, was discovered by Dr. L.H Robbins and B.M Lynch. They were both working in the northwestern part of Kenya, the Lake Turkana area to be precise. The Namoratunga is an area that holds 19 stone pillars and is said to have been built around 300 BC (this is still a speculative date estimate). It was built to represent the rising positions of the seven stars that make up the Borana calendar. If the speculated time of the Namoratunga development is correct, then the Borana calendrical system has been in existence 1800 years before the creation of the present-day western Gregorian calendar.

After careful consideration and measurements were retaken, Mr. Robert Soper, an anthropologist in Kenya, discovered that the pillars had magnetic properties. Despite the slight irregularities, the measurements were modified to fit the new discovery and alignment of the stars were still found. With many uncertainties regarding the pillars and its connection to the stars and ayantu discoveries, researchers decided to seek answers astronomically.

The term ‘new moon’ means that the moon is close to the sun and can be seen just after sunset or just before sunrise. When it is twilight time, it almost impossible to see the moon next to Beta Triangulum, and this is one of the most important observations that make up the Borana Calendar. This could cause confusion as the next new moon will rise behind the Pleiades, and the third moon will completely skip Aldebaran and rise with Bellatrix. This is not how the Borana Oromo culture calculates or describe their calendar.

If we take conjunction to mean rising with (in the same position), and not rising next to, then the Borana description of their calendar works. Beta Triangulum rising at a certain position within the horizon could be used to determine the new year. Under this different interpretation, astronomists could see the next new moon rising in the position of Pleiades, and the following new moon rising with the Aldebaran position, and so on.

These anthropological and astronomical results are quite fascinating as these make up the derivation of a calendrical system. Despite changes, the horizon positions are marked on the Namoratunga pillars, and this allows the ayantu to observe the monthly rising position correctly. Since the stars no longer rise in the correct horizon position, these markings are needed for the accurate derivation of the days and months of the calendar.

(1) Beta Triangulum
: The brightest star with a magnitude of 3.0 in the northern sky. A small constellation in the Triangulum.

(2) Pleiades: Located within the Taurus constellation, the Pleiades are blue star clusters also known as Messier 45 and Seven Sisters

(3) Aldebaran: A red giant star also under the Taurus constellation.

(4) Bellatrix: Under the Orion constellation and represents its shoulder, Bellatrix is the third brightest star.

(5) Central Orion: This is the region around the belt and sword of Orion

(6) Saiph: This is the sixth brightest star within the Orion constellation and represents the right knee of Orion.

(7) Sirius: Under the Canis Major constellation, it is the brightest star in the night sky and is also a binary star.


This site uses Akismet to reduce spam. Learn how your comment data is processed.