French geo-archeologist Richard Oslisly (centre) and two French anthropobiologists Sebastien Villotte (left) and Sacha Kacki examine the remains of a skull in the Iroungou cave near Mouila in Gabon, March 2 2020. Picture: PASCAL MORA / ARCHEOVISION / AFP
French geo-archeologist Richard Oslisly (centre) and two French anthropobiologists Sebastien Villotte (left) and Sacha Kacki examine the remains of a skull in the Iroungou cave near Mouila in Gabon, March 2 2020. Picture: PASCAL MORA / ARCHEOVISION / AFP

Libreville — The discovery of a 14th-century underground burial site deep in Gabon’s tropical forest may shed light on a little-known period in Africa’s history.

Hundreds of medieval artefacts are scattered with human remains at the bottom of a cave in the southeast of the country, discovered by a French geo-archaeologist in 2018.

“This is a unique discovery in Africa, because human remains are almost nonexistent,” said Richard Oslisly, who is leading an expedition financed by Gabon’s National Agency of National Parks.

The mission is also funded by the local environmental branch of Singapore’s palm oil giant Olam International, which is well established in the west African state.

There are no golden platters or diamonds at the end of the 25m of rope needed to reach the floor of the cave, but the site named Iroungou is still a treasure trove for scientists.

Almost 30 skeletons have been discovered on three levels, together with more than 500 artefacts,  mostly made of iron, that range from knives, axes and spear tips to bracelets and collars. Researchers also found 39 pierced teeth from hyenas and panthers.

Oslisly, 69, began to speak of the discovery only a year afterwards, but it has caused a wave of excitement and hope in the regional scientific community.

“This cave will enable us to find out a little more about these peoples of central Africa, largely unrecorded in history,” the French researcher said in his Libreville office.

In Sub-Saharan Africa, “soils are very acidic, so everything of human and animal origin decomposes very quickly”, said Geoffroy de Saulieu, an archaeologist with France’s Research Institute for Development (IRD).

“It is exceptional to obtain this kind of remains.”

Carbon-14 dating on 10 femurs, or thigh bones, found in the cave placed the skeletons in the 14th century, which is a worthwhile discovery in itself.

Vestiges of the past are unusual in this part of the world, but that is also partly because archaeological research is rare and generally underfunded.

The first written texts regarding Gabon came from European explorers who landed on its Atlantic Coast at the end of the 15th century. It was not until the 19th century that explorers ventured far inland on territory almost completely covered with forest.

The oral record of indigenous clans and families handed down in villages “doesn’t let us go back further than one or two centuries”, said Louis Perrois, a French anthropologist who has studied oral tradition in much of Gabon since the 1960s.

When researchers questioned the elders in villages around the Iroungou cave, nobody was aware of the existence of the site. The villagers said they had no idea who the men and women buried there could be.

Molar teeth extracted from skulls have been sent to France for DNA testing. Scientists can also count on a DNA base compiled with saliva data from peoples across central Africa.

Oslisly hopes to “cross-check the data and, perhaps, to find the descendants of these skeletons”, with the DNA tools used by linguists.

In March, a team of anthropologists and specialists in bone pathology — people with skills to diagnose illnesses from remains — were due to go down into the cave.

“We’re going to find out more about the diet of the buried people, and the illnesses they have contracted during their lives,” says Oslisly, who is still enthusiastic after 35 years of work in Gabon and Cameroon. “Above all, we're going to learn what they died of,” he said.

Apart from a collective burial site unearthed at Benin City in southern Nigeria in the 1960s, Iroungou is the only cave grave to be found in Africa. The Benin City site has also been dated to the 14th century, an epoch which witnessed the fall of many African civilisations, according to several historians.

Some researchers wonder whether Africa was struck by a bubonic plague that struck Europe and Asia over the same decades. Maybe the Iroungou bones hold an answer.

“In Benin City, the ADN was not saved, but in Iroungou the bones are in very good shape,” De Saulieu says.

AFP