 The Roman Empire was one of the greatest empires in human history, but what was the genetic makeup of ancient Rome during the imperial phase when the Roman Eagle was flying high above the Mediterranean? How much influence, if any, did other parts of Europe or North Africa or the Middle East have on the genetic makeup of ancient Rome? I will answer these and many other questions in this video. Now the Roman Empire has a certain allure, it is certainly one of my favourite empires in human history, but before we look at the genetic makeup of ancient Rome, let's get a general overview of the different phases of ancient Rome. Broadly speaking, the story of ancient Rome begins in the 8th century BC with the formation of the Italian city of Rome, which evolved into the Roman Kingdom which existed from 753 to about 509 BC. Then the Roman Republic was formed and lasted from 509 to about 27 BC. A few decades after Julius Caesar crossed the Rubicon, Rome became an empire, with the Roman Empire existing from 27 BC up until 395 AD. During its imperial phase, it was amongst the largest empires in the ancient world, with an estimated 50 to 90 million inhabitants, roughly 20% of the world's population at this time. Estimates of the population size of Rome itself are between around 500,000 people, to some estimates as high as 1 million people, at its peak. The empire covered around 5 million square kilometres, or around 1.9 million square miles, at its zenith in 117 AD. Nothing lasts forever. The western Roman Empire collapsed in the 5th century AD when it was overrun by various Germanic peoples. Now we have a better understanding of the different phases of ancient Rome, let's turn their attention to its genetic makeup. Luckily a comprehensive study was done in 2019 led by researchers from Stansford University. In a paper titled Ancient Rome, a genetic crossroads of Europe and the Mediterranean, the study analysed 127 genomes from 29 archaeological sites in and around Rome, spanning the last 12,000 years, showing the changes in the genetic makeup of Rome from the very early period through to the republican period, the imperial period and after its fall. The oldest genomes in their dataset are from three Mesolithic hunter-gallerars, that lived around 10,000 to 7,000 BC, from a cave in the Apennine mountains that run through Italy, with their genetic makeup being very close to western hunter-gallerars from elsewhere in Europe. Now the first major ancestral shift in the genetics of Rome occurred between 7,000 and 6,000 BC, coinciding with the transition to farming and the introduction of domesticates, including wheat, barley, pulses, sheep and cattle into Italy. Similar to early farmers from other parts of Europe, Neolithic individuals from central Italy are close to Anatolian farmers. However, Admixture reveals that, in addition to ancestry from northwestern Anatolia farmers, all of the Neolithic individuals that we studied carry a small amount of another component that is found in high levels in Neolithic Iranian farmers and Caucasus hunter-gallerars. So although these Neolithic individuals have a good amount of ancestry from Anatolia, modern-day Turkey, they also have ancestry further east of this, around Iran and the Caucasus, which is quite interesting. This fact actually makes Italy quite distinct from other parts of Europe, as the study notes, as other parts of Europe carry farmer ancestry predominantly from northwestern Anatolia, with these findings from Italy pointing to different or additional source populations involved in the Neolithic transition in Italy compared to central and western Europe. So this is the first major ancestral shift in Rome, but what about later transitions? Well the study notes that the second major ancestral shift occurred during the Bronze Age, and a period between 2900 and about 900 BC. The reason that this is quite a broad period is because the study couldn't fully pinpoint, the researchers couldn't fully pinpoint the exact date, but it did happen within this time period. The study basically looked at 11 Iron Age individuals dating from 900 to 200 BC, so it includes the republican period of Rome. In this group shows a clear ancestral shift from the Copper Age, interpreted by Admixture as the addition of a steppe-related ancestry component and an increase in the Neolithic Iranian component. The study modelled the genetic shift by an introduction of around 30 to 40% ancestry from Bronze and Iron Age nomadic populations from the Pontic Caspian steppe, similar to many Bronze Age populations in Europe. The presence of steppe-related ancestry in Iron Age Italy could have happened through genetic exchange with intermediary populations. Additionally, multiple source populations could have contributed, simultaneously or subsequently, to the ancestry transition before the Iron Age. By 900 BC at the latest, the inhabitants of Central Italy had begun to approximate the genetics of modern Mediterranean populations. Now followers of this channel know how often steppe-related ancestry shows up in the historical ancestors of different populations across Europe. I've covered this in various other videos, and I've also covered the different archaeological cultures to help spread this steppe-related ancestry from the Yamnaya people to the Bell Beaker people, and I suggest if you haven't seen them already, watch them after this video because it's really interesting and a fascinating part of history that is often not really discussed. There is also a good amount of variation in these samples, as the authors point out. The Iron Age individuals exhibit highly variable ancestries, hinting at multiple sources of migration into the region during this period. The study further states that although we were able to model eight of the eleven individuals as two-way mixtures of Copper Age Central Italians and a steppe-related population, this model was rejected for the other three individuals. Instead, two individuals from Latin sites can be modelled as a mixture between local people and an ancient Near Eastern population, best approximated by Bronze Age Armenian or Iron Age Anatolian. And a Truscan individual carries significant African ancestry as well, identified by F statistics, and can be modelled with 53% ancestry from late Neolithic Moroccan. Together, these results suggest substantial genetic heterogeneity within the Truscan and Latin groups. Now this is where things get really interesting. During the republican and imperial period, Rome expands across the Mediterranean area and into three continents. The empire facilitated the movement and interaction of people through trade networks, neuraled infrastructure, military campaigns, and slavery. Beyond the boundaries of the empire, Rome engaged in long-distance trade with northern Europe, sub-Saharan Africa, the Indian continent, and across Asia. So what impact did this expansion have on the genetic makeup of Rome? Now I know what you're thinking, that's a really nice jumper you're wearing, and you'd be right. If you want to pick up one of these for yourself and check out my merch store in general, please click the top link in the video description below and use the code history at checkout for 5% off your order. Thank you and now on with the video. Well, as the study found, during the imperial period, the most prominent trend as an ancestral shift towards the Eastern Mediterranean and with very few individuals of primarily Western European ancestry. The distribution of imperial Romans largely overlaps with modern Mediterranean and Near Eastern populations, such as Greek, Maltese, Cypriot and Syrian. This shift is accompanied by a further increase in the Neolithic Iranian component and admixture and is supported by F statistics. Compared to Iron Age individuals, the imperial population shares more alleles with early Bronze Age Jordanians, as well as for Bronze Age Lebanese and Iron Age Iranians. Furthermore, the study revealed diverse ancestries amongst imperial individuals who fall into five distinct clusters. Notably, only two out of 48 imperial era individuals fall into the European cluster to which 8 out of 11 Iron Age individuals belong. Instead, two thirds of imperial individuals belong to two major clusters. They overlap with the central and eastern Mediterranean populations, such as those from southern and central Italy, Greece, Cyprus and Malta. An additional quarter of the sampled imperial Romans form a cluster defined by high amounts of haplotype, sharing with Levantine and Near Eastern populations. There is no pre-imperial individuals appear in this cluster. Some of the individuals in this cluster also project close to four contemporous individuals from Lebanon. In addition, two individuals belong to a cluster featuring high haplotype, sharing with North African populations and can be modelled with 30-50% North African ancestry and explicit modelling. This table from a Stanford video they released detailing the study shows a good overview. Compared to the Iron Age or Republican period in Rome, the imperial period shows a clear shift to the east, with Rome's genetic makeup being around 4% North African, 40% Eastern Mediterranean, 28% Near Eastern, 4% European and 24% Mediterranean. In the words of Jonathan Prickhart, a professor in the departments of genetics and biology at Stanford University and an author in this study. So one of the most interesting things that we see is that during the first century CE, which is really the heart of the imperial period, we see at that time that there's a huge amount of immigration that's coming into Rome, mainly from the Near East, coming either directly or indirectly. And that's enough to actually shift the average ancestry of people who are living in Rome to look much more Eastern at that time. So there you go. That is the genetic makeup of ancient Rome. Very interesting. It's interesting to be such a shift to the east during the imperial period. It also leads to the question, why did it shift so much to the east? And that's perhaps a research question for a different time for a later time. Perhaps simply if you look at the map of Rome relative to the rest of the empire, obviously there was quite a lot of people east of Rome. So potentially just given the expansion of the empire and so much mixture with people from the east and people moving back to Rome. That would perhaps explain it by interest and research question for a future time. Why there was such a shift to the east? Now in a future video I'm going to look at the genetic legacy of the Roman Empire on different parts of Europe, a video I'm very much looking forward to, but that's a story for another time. One interesting feature in this video has been the introduction that we see in so many different cultures of steppe-related ancestry during the Bronze Age. One culture that helped spread steppe-related ancestry and was instrumental in this was the Yamnaya culture. To find out more about the Yamnaya, please click here. Thanks for watching. Please subscribe and hit the bell. To pick up this jumper and check out my merch store and help support this channel, please click the top link in the video description below and like I say you can use the code HISTORY for 5% off your order. But thanks again for watching. 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