Could an ancient children's burial ground contain clues about how one of the world's greatest empires came to an end? Andrew Thompson explores the theory that malaria was the silent killer responsible for the fall of Rome.
Roman fever Today in the west, most people have forgotten how deadly malaria used to be, although there were serious malarial epidemics in many parts of Italy as recently as the 1950s. But each year, mainly in Africa, it still kills over two million people, most of them children. While there are several mentions of a disease sounding very similar to malaria in historical documents from Roman times, there has never been any hard evidence of its presence.
But last year, for the first time, a British scientist proved conclusively that the most dangerous type of malaria was a killer in imperial Rome. The scientist relied on the latest DNA techniques that are revolutionising the understanding of the role of disease in ancient times. The malarial DNA from a Roman site, dating from around AD 450, is the oldest definite evidence of malaria in history. The finding of malaria was a remarkable and complicated piece of detective work, which spanned the last ten years.
At its height, the Roman Empire stretched from Scotland in the northern hemisphere to the deserts of Africa in the south. The empire lasted for over 500 years, although its eastern part, the Byzantine Empire, lasted for several more centuries. When the empire collapsed, hordes of barbarian armies, including the infamous Vandal pirates, invaded Italy throughout the fifth century AD. Rome was transformed from a bustling city of millions to a provincial town of a few thousand, surrounded by swamps. The anarchy of the Dark Ages had begun.
Although there has been no shortage of theories, it has never been clear why Rome became so vulnerable to foreign invaders at this time. Political instability, the collapse of food supplies to Rome, and even the infamous lead in the water supplies have all been implicated. Historians have generally agreed that Rome's downfall was due to a combination of many factors.
The children of Lugnano One element that has largely been ignored by researchers is the role of disease and epidemics in contributing to the fall of Rome. David Soren is the American archaeologist behind the new theory that malaria played a key part. He is an expert on Roman antiquity, having dug at several sites in the Mediterranean area. Ten years ago he was invited to a beautiful hill town called Lugnano (just north of Rome) by local archaeologists. They wanted Soren to help them excavate the remains of a Roman villa outside the town.
At first Soren thought it would be a fairly straightforward excavation. But it wasn't long before he came across something totally unexpected. In the store rooms at the back of the villa he and his team found the skeleton of a baby, buried in a pottery storage jar (an 'amphora'). That same day his team found seven more child skeletons, and soon more and more babies were being uncovered. In the end Soren and his team excavated 47 children. The oldest was just three years old, most were much younger: over half had died in the womb. It is the largest children's cemetery ever found from Roman times. But the large number of children was not the most unusual thing about the site.
As they uncovered the babies the archaeologists began to find the remains of puppies. It soon became clear that these puppies had been sacrificed, they had literally been torn apart and then placed in the grave as part of the burial ritual. Most of them had been decapitated. There were also signs of burnt plant offerings. All this was a puzzle to David Soren, because at the time of the burials most of the citizens of the Roman Empire were ostensibly Christian. Soren believed that whatever it was that was killing the children must have been so terrible that the parents were afraid of it. That was perhaps why the villagers had rejected Christianity and reverted to pagan practices.
A deadly epidemic Over the next few years Soren pieced together all the evidence that might help to explain what the villagers were so afraid of. From careful excavations of the site he knew that all the babies had been buried over a very short period of time, probably just a few months at most. Some of the bones of the children showed evidence of some type of blood disease. And many of the plant offerings were of honeysuckle, a plant commonly used in the treatment of fevers by the Romans. Soren believed it was a deadly epidemic, and most likely malaria. Roman writers in the area of Lugnano had specifically mentioned that there was a zone of pestilence in this region and that people died of fevers.
Soren's most important ally in Italy was one of the world's leading experts on malarial mosquitoes - Professor Mario Coluzzi of the University of Rome. Independently of Soren's work, he had been investigating the spread of malaria out of Africa and into Italy and the rest of southern Europe. Coluzzi believed that malaria was not a problem at the beginning of the Roman Empire, but had become increasingly serious as the empire declined. It is known that malaria originated in central Africa and then spread north. Coluzzi was most interested in working out when it first arrived in Italy, and how it got there.
Widespread trade Key to Coluzzi's ideas was the thriving trade throughout the Mediterranean region during Roman times. Coluzzi believes that one way the malaria reached mainland Italy was by cargo ship. Passengers on the boats could be carrying the malaria in their bloodstream even before showing symptoms. The water barrel on board could contain mosquito larvae.
There is now more and more archaeological evidence of widespread trade. Last year, at the ancient harbour of Olbia on the island of Sardinia, 16 Roman cargo ships were found buried in the mud. They were extremely well preserved, many of them still had their wooden decking intact, and they have now been carefully excavated. Pottery on board was further proof of trade between North Africa and Rome. Sardinia was almost certainly a stepping stone for the malaria parasite, before it reached mainland Italy. Coluzzi's research indicates that the most serious type of malaria (known as plasmodium falciparum) reached Rome at about the time of Christ.
Even though Coluzzi's work dovetailed nicely with Soren's theory about the children of Lugnano, most archaeologists, especially in the United States, were extremely skeptical of the malaria hypothesis. Soren received huge amounts of criticism from fellow archaeologists, who argued that the infant burials may have happened over a long period of time, and that even if it was an epidemic it was likely to be some other disease. Although Soren himself was convinced he was right, few believed him and his research was marginalised.
Malarial DNA It was in the late 1990s that a British scientist first heard about David Soren's work on the children of Lugnano. Robert Sallares was a DNA expert based at UMIST (University of Manchester, Institute of Science and Technology). He was particularly interested in using the latest DNA techniques to identify diseases of the past. His main problem was finding bones that might be associated with a particular disease. There was no point in looking randomly at bones from the past, he needed to know that there was a good chance that the person had died of a particular disease.
At first Sallares was unable to find suitable bones, but when he read about Soren's work, he approached him about doing DNA tests. Soren jumped at the opportunity. Not only did Robert Sallares take his theory seriously, but now, for the first time, there was a forensic technique that would give cast-iron evidence either way as to the presence of malaria. Sallares and his team painstakingly analysed the bones, searching for the tell-tale DNA traces of the disease.
The first four results all came up negative. It was not until Sallares tried the fifth and last bone samples that he finally came up with a positive result. He was able to show the presence of malarial DNA in the leg bones of a three-year-old girl. Because of the way malaria spreads, this particular malaria was most likely part of an epidemic sweeping through a region of Italy.
The use of DNA probes to identify diseases of the past has recently been applied to many other diseases, including the black death. It is particularly useful in diseases that do not leave tell-tale signs of symptoms on the bones of victims - which applies to most diseases. For instance, people who die of syphilis have very distinctive malformations on the skull, but malaria only causes signs of disease in some bones - so usually it is only by means of a DNA test that scientists can be positive that malaria was present when someone died.
The DNA work of Robert Sallares has now confirmed that malaria was a killer during late Roman times. The children of Lugnano died of malaria, and it is likely that there were also many adult victims of the disease, although their cemetery has not yet been found. This would have made it difficult for farmers to collect crops and for the local army commanders to raise troops. What was once a footnote in the history books on the fall of Rome, must now become a whole chapter. David Soren's theory that malaria contributed to the fall of Rome has finally been vindicated.