adminBy Takaendesa Denhere
There is little or no proper documentation of the achievements of our great, great grandfathers. Focus in this article is going to be put on Great Zimbabwe, an ancient Shona state that harnessed solar energy more than us. It was once a powerhouse that began from the 11th century into the 15th century, built by the Gumanye clan. The Gumanye were a small, elite Shona group on the Zimbabwean plateau that was so rich and powerful enough to conquer all other Shona clans making them their subjects.
The sun played a very pivotal role shaping the Shona society, culture, science as well as driving the economy. It stimulated economic growth to an extent that we can liken it to ancient European giants like the Greek and the Roman Empire.
There were no mechanics to actively tap sun energy like we do, so they used solar energy passively. There were different sources of energy used during the time which had a tiny carbon footprint compared to today.
In scientific innovations, the Shona used the sun to gauge time their day-to-day living. Although it was not precisely accurate, they dealt with approximate time.
This was a basic way to understand the time of the day because they did not have scientific instruments for the purposes of measuring time.
For example if the sun was rising it was deemed to be morning, if the sun was positioned right above, it was noon and sunset meant evening.
On the other side of the world, the Roman were a bit advanced because they were using sundials and water powered clocks to ascertain time.
The calendar system was developed based on the sun movement to tell the various seasons which they went through. Naturally, seasons are caused by the circling of the earth around the sun as well as orientation of the earth when it tilts on the axis at an angle of 23,5 degrees. The Shona knew that when the sun’s rays were weak, lower and closer, tilted from the sun it was winter. In summer the sun is higher, stays above the horizon for longer and the rays are more than direct. Zhizha was the farming season, chirimo was the after harvest season, chando was winter and autumn was called madzudzo. Up to now we are still using this standard.
When you compare with the present and the Great Zimbabwe times you will discover that back then there were huge expanse of forests and unoccupied spaces. To survive, the ancient man had to take resources from the environment, for example firewood as fuel and construction materials as well as hunting so they had to go deep into these forests. Most of the time they used landmarks, like mountains, hills and rivers as reference points for direction but when this did not apply they used celestial bodies — observation of the position of the sun.
Magnetic compasses that we currently use were unknown to them so the sun-compass was used to study the position of the sun’s shadow to tell which way the north is. The hunters and gatherers who navigated in the jungles had acute astronomical knowledge which was sufficient to use the sun to determine where they were headed.
Great African explorers like Nyakatonje, Nyatsimba Mutota navigated all their way to the north of the state in the Zambezi and brought back a lot of treasures from the Dande area. The exploration expedition led to the rise and establishment of another vibrant state, the Mutapa State, which superseded Great Zimbabwe and was even more powerful.
When we look at the food consumed in the state they ate both fresh and dried food. Fresh food by nature begins to spoil the moment it is harvested and cannot last long. Once it overstays it has to be thrown away and to avoid wasting they dehydrated the food, removing water and moisture using the sun. Dried foods stay for a very long time because it is not affected by the actions of moulds, yields, bacteria and enzymes.
The advantages of drying food were that of long preservation, it could be eaten at any time in all seasons, easy to transport and reduced storage space.
Grain was dried on large surfaced rocks (ruware) and it included sorghum, beans, finger millet and bulrush millet. After drying they were put in custom-made granaries for storage.
It is said that the grain could last for around seven to 10 years. Grain was reserved for relief during the times of famine as well as feeding the visitors or foreign emissaries from other kingdoms or faraway places like Portugal and Arabia.
Solar energy also sustained economic activities that strengthened the Great Zimbabwe state economy making it an indomitable super power during the period. They had men with special skills of tanning. Tanners were able to treat animal skins to produce leather. Leather was used because of its durability to make clothes and blankets as well as sitting mats. It was used in local barter trade within the state making it a very valuable form of currency because their economy was not monetised.
In international trade animal skins treated by the same tanners were shipped overseas. The Great Zimbabwe economy heavily relied on exporting and importing various goods. They exported special skins to overseas countries like Portugal and Arabia. The skins included cheetah, leopard and elephant skins. With these skins they were able to import highly priced goods like Chinese porcelain and Portuguese cloth.
Revenues were also accrued at tolls (so the toll gating system is not new to the Zimbabwe) where foreign merchants like the Swahili and Muslim who were the importing agents of the Portuguese were forced to pay toll fees which they called curva making the state an economic giant
Craft-work specialists took advantage of passive solar energy too especially basket makers and potters. To make baskets they used wet moist reeds when making and after that they would expose them to the sun until they had dried. The dried products would be ready for shipment and trade as well. This is also the same with pottery-making process.
Potters would make their pottery which they would dry in the sun and they would heat them up in intense fire for strengthening.
The use of the solar system to gauge time and navigation, as well as economic development led to the creation of a very powerful army of the state which played a very pivotal role in the expansion of the state across the Zimbabwean plateau, between the Zambezi and the Limpopo rivers.
The Gumanye military strength and prowess gave them the ability to conquer and police large areas which brought revenues in the form of tribute, taxes. Comparing with the contemporary times the army supported and maintained territorial integrity of the kingdom through tax collection, we can say that they were the earliest Zimra officials.
Takaendesa Denhere is an independent researcher and writes on renewable energy. For feedback contact him on his email: [email protected]
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