 What was the genetic legacy of the Roman Empire on the territories it controlled? At its peak in the 2nd century AD, the Roman Empire controlled around 20% of the world's population. In my last video I looked at the genetic makeup of ancient Rome itself, but in this video I want to look at the genetic legacy of the Empire more broadly. Now a lot has been written on the legacy of the Roman Empire in general, from improvements in sanitation to architectural, engineering, political, legal, linguistic and countless other areas of life that the Romans, the ancient Romans influenced. But little has been said about genetics. What impacted one of the greatest empires in human history, having the genetics of people who lived under the Roman yoke? Now let's start in Britain. The Roman influence on Britain began in earnest with the invasion of 43AD and lasted for nearly 400 years, until 410AD. The Roman occupation of Britain was not necessarily smooth, exemplified by the fact that they had to build two major defensive walls on these lands to solidify their position, Antonine's wall in modern Scotland close to where I grew up and Hadrian's wall in the north of modern England, which was built as the biographer of Hadrian famously said, to separate the Romans from the barbarians. Now considering that the Romans occupied Britain for hundreds of years, you would probably think there would be quite a significant genetic marker, genetic legacy left by the Romans. But is this true? Well the people of the British Isle study looked at the different invasions and migrations over the centuries of millennia and the impact they had on the genetic makeup of Britain. It seems, however, that there was a very limited genetic legacy left by the Romans in Britain. One theory by this is the case is potentially because only small numbers of Romans actually settled in Britain long term. Furthermore, many people have also argued that even parts of Britain that were technically under Roman control, many rural parts of Britain were probably relatively unaffected by Roman rule and practically on a day by day basis, they lived their lives quite similarly than before. The Romans obviously would have been concentrated in their defence of fortifications in the major towns they built up, but not necessarily in rural communities, and there might have been quite limited interaction between the Romans and the native populations. Obviously in the 5th century AD as well, when Roman rule ended in Britain, yay, all the Roman legionaries and the high ranking Roman officials were obviously recalled back to Rome and redeployed to different parts of the empire. There is much more to the story, however. If we look at another corner of the empire, much more to the east, we see some really fascinating insights into the genetic legacy of the Roman Empire and how the Roman Empire changed the ancestries and genetics of certain areas. Genetic research has been done in the Balkans, for instance, particularly in modern De Serbia, around a major Roman city and stronghold that was established in the 1st century AD called Viminisium, which is near the modern town of Kostalac. Viminisium was the capital of the Roman province of Moisia in the Balkans, which sat just south of the Danube River, a natural barrier for the Romans. A fascinating study was published last year in the journal Cell, which looked at the genetic history of the Balkans from Roman frontier to Slavic migrations. The authors begin by detailing the importance of this region from a Roman strategic perspective. From the 1st to the 6th century CE, the Roman Empire's middle Danube frontier in present-day Croatia and Serbia was a zone of defence, confrontation and exchange with populations living north of the frontier. This region is also a source of significant mineral wealth and a crucial hinge and a 2,000 kilometer long corridor of military and communications infrastructure linking the Black Sea to the Black Forest. Following the establishment of Roman control in the 1st century CE, the region became increasingly urbanized and culturally Romanized. Between 268 and 610 CE, more than half of all Roman emperors belonged to families originating in the middle Danube. Constantine the Great, who was the first Roman emperor to convert to Christianity, was born in Moisia, for instance. But what about the genetic impact, what we're all here for? Well, before we get on to the key finding of this study, the authors initially looked at the potential genetic impact of the Italian peninsula itself on the Balkans, as the authors wrote. Despite the exceptional number of Roman colonies in the region and the large military presence along this frontier, there is little ancestry contribution from populations long established in the Italian peninsula. A pattern exemplified by the almost complete absence and their Balkan on Y chromosome lineage, R1B U152. The most common paternal lineage and bronze age in Iron Age populations in the Italian peninsula. Rome's cultural impact on the middle Danube was deep, but our findings suggest it was not accompanied by large-scale population movement from the metropolis, at least by the descendants of central Italian Iron Age populations. However, what this study did find was that the Roman Empire shifted the genetics of the Balkans in a similar fashion to how the genetics of ancient Rome itself changed during the imperial period. The Roman Empire did, however, stimulate demographic change in the Balkans. In this early period, one out of three individuals, or around 15 out of 45, fall beyond the Balkan clines and PCA by close to Near Easterners, and can be modelled as deriving their ancestry predominantly from Roman Byzantine populations from Western Anatolia and, in one case, from Northern Levantine groups. A very strong demographic shift towards Anatolia is also evident in Rome and Central Italy during the same period, and demonstrates long-distance mobility plausibly originating from the major Eastern urban centres of the empire, such as Ephesus, Corinth or Byzantium Constantinople. Our results show that these migrants had a major demographic impact not only on the imperial capital, but also on large times of the empire's northern periphery. So how interesting is that? In my last video, I showed how research from Stanford University showed that during the imperial phase, the genetics of ancient Rome itself shifted to the east, with a large introduction of Near Eastern ancestry, and a similar pattern seems to have followed in the Balkans. This study also found some really interesting outliers. There was a male, for instance, that had East African ancestry, who was buried with an oil lamp decorated with Jupiter-related eagle eye chronography, a clear Roman symbol. Although too much can be read into this, and we don't know his life story, whether he was a soldier, a merchant, a migrant or whatever else. This fine certainly speaks to how the Roman Empire increased the movement of people around the Mediterranean. Now, I should note as well, particularly because I'm Scottish, that the Romans ended many genetic lines with brutal genocides. For instance, by Julius Caesar's conquest of Gaul, considered the genocide by many, I know Dan Carlin done a really good hardcore history on the conquest of Gaul, the genocide in Gaul, with some ancient sources suggesting that one million Celts were killed in this genocide, although many have argued that's probably exaggeration to a large extent, but still hundreds of thousands of people probably died in this genocide. There was also brutal campaigns in modern day Scotland, ancient Caledonia to the Romans under Septimius Severus. The many would say constitute a genocide, or certainly had the intention of genocide. In around 209 or 210 AD, a force of around 50,000 Roman troops invaded ancient Scotland to squash a rebellion from a confederation of tribes known as the Mai Tai. As the Romans pushed north, they killed thousands of Mai Tai in Caledonians and a brutal campaign that reached as far as Aberdeenshire. The Romans claimed that the Mai Tai had broken a peace treaty, although who knows if this was just an excuse for conquest. This campaign was led by the Roman Emperor at the time, Septimius Severus, who according to the Roman historian Dyle, gave the following genocidal speech to his troops. We are not going to leave a single one of them alive, down to the babies in their mothers' wombs. Not even they must live. The whole people must be wiped out of existence, with none to shed a tear for them, leaving no trace. It does appear that Dyle borrowed this speech for dramatic effect, taking it from Homer's The Iliad about the Trojan War. However, Severus' orders and mindset were probably not too far from the tone of this speech. This is all to say that despite the allure of the Roman Empire, it was built on the back of brutal conquest in many instances. Now if anyone has come across any really good sources on the genetic legacy of the Roman Empire, please get in the comments below. I'd be really eager to read them. When I was doing research for this video, I didn't find as much information on the genetic legacy of the Roman Empire as I had hoped, and probably for good reason to be honest. Obviously one defining feature of the Roman Empire in general was the fact that they allowed foreigners to join their army, and they were incorporating lots of foreigners into their army, which obviously meant that the genetic makeup of the Roman army was actually quite fluid. There is obviously some interesting insights that we have found, particularly in the Balkans, when we saw a clear genetic shift to the east, with the Anatolia being more introduced into the Balkans during the imperial period, whereas in Britain we don't really see any real genetic legacy left. So it is interesting how different corners of the empire had different genetic legacies. But what about the genetic makeup of ancient Rome itself? Quite a lot of research has been done into this, and there's lots of fascinating insights. To find out more about the genetic makeup of ancient Rome, please click here. Thanks for watching, please subscribe and hit the bell, tell your friends and family about this channel, please also let me know your thoughts in the comments below. But thanks again for watching and I'll see you next time.