I read many biased and politically driven answers on this question, which is honestly sad. Take everything you read here with a grain of salt, considering there are many people with agendas.
By: Michael Constantine Dimopoulos
I will try to provide an in-depth answer based on data and conclusions from anthropological, historical, genetic as well as linguistic studies. Thankfully, I have enough time.. so, this is going to be long.
If you are looking for a quick answer then know that nobody is “pure”. Every population is mixed to a certain degree. With that in mind it should be noted that there is a strong genetical connection between the modern and ancient populations of the areas around the Aegean Sea (Greece). According to geneticists : “Our results support the idea of continuity but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations” which seems to be the most credited and quick answer, but more on genetics later. It is important to know that people native to certain region have genes from all the previous civilizations of this region. People don’t just disappear.
I read in another answer that the modern Greek state was an artificially made state. I fail to understand how this is related to the topic. Somebody who has attempted to answer this question also said that it was the first modern Greek state, which is simply incorrect. The first modern Greek state (that is an ethnically Greek state after the fall of Constantinople in 1453) was the Septinsular Republic , and that was the only Greek state that didn't exist during the medieval times, because we have many other ethnically Greek states that were founded before the fall of Constantinople, but survived until after 1453: the post 4th Crusade states. Those include the Empire of Trebizond (survived until 1461), Despotate of Epirus (survived until 1479), Duchy of Athens (survived until 1456) all of which were ethnically Greek states that existed after the fall of Constantinople, therefore modern Greek states. Also, let's not forget the Kingdom of Morea as well as the Despotate of Morea - again ethnically Greek states. Oh yeah, also: the Kingdom of Thessalonica, the County Palatine of Cephalonia and Zakynthos, the state of Lemnos, the empire of Nicaea, the Latin empire, County of Salona, Principality of Achaea, the Marquisate of Bodonitsa, Duchy of Naxos, Triarchy of Negroponte. All of those were short-lived (for the most part) states founded by the Latins, but they were ethnically modern Greek states, inhabited almost entirely by Greeks. Even the Duchy of Philippopolis was mostly Greek - and it was in Bulgaria. And there are a lot other neo-modern Greek states after the Ottoman occupation as well (Cretan State, Principality of Samos, State of Northern Epirus, Republic of Cyprus and of course the Hellenic Republic or Modern Greece) most of which united with modern Greece, which, very simply, proves that “modern Greek” is not just a political term related to citizens of the modern Greek state, but an ethnicity irrelevant to state. If we followed the same logic then medieval citizens of the Holy Roman Empire in the region of Germany were not Germans because they didn’t live in the modern German state. Idiotic, isn’t it? I would not trust an answer given by somebody with such bad knowledge of history.
Also, there are many people referred to as “Greek" before the Greek state, especially in eastern Anatolia (Constantinople, Smyrna). The Greek identity became more common among Greeks after the 4th crusade. Before that, they generally carried the “Roman" identity with them. The west always referred to them as Greeks, to keep them away from the title of the Roman, which sort of kept the Greek identity alive. No matter which year you choose from ancient Greece to today, there will always be a reference to the Greek people, around the Eastern Mediterranean, speaking Greek. There are many modern Greek noble families that can trace their origins back to medieval Greece and the Byzantine empire, some even the Roman empire (Vlastos - Wikipedia ). After the fall of Constantinople (1453), many Greeks moved to the west and became scholars of the Renaissance (Greek scholars in the Renaissance - Wikipedia), and from the mid 1400s until almost the 1900s, in the west “Greek" was synonymous with noble, wise and educated, because the only Greeks that went to Europe were typically the educated ones from noble families.
It is not too far stretched to suggest that modern Greeks are related their ancient predecessors, as most anthropologists agree that they are related to the peoples of the region even before the Mycenaeans ( that is, the ancestors of the ancestors of the ancient Greeks). First of all, we should clear up that it is almost a fact that there is a connection between the ancient and modern inhabitants of Greece. The main argument is about how close they are. I will try and defend the most popular opinion of the two. We have a lot to cover, so I better start now.
Anthropologically
Before we get into Anthropology note that a large part of “Racial Anthropology” is nothing more than scientific racism and falls under the category of pseudo-science. Racial Anthropology itself, however, is very real, and it’s a pity that it is abused to a point where it becomes a fake and misleading pseudoscience.
"It is inaccurate to say that the modern Greeks are different physically from the ancient Greeks; such a statement is based on an ignorance of the Greek ethnic character... The Greeks, in short, are a blend of [sub]racial types, of which two are most important: the Atlanto-Mediterranean and the Alpine. Dinaricism here is present, but not all-pervading; true Alpines are commoner than complete Dinarics. The Nordic element is weak, as it probably has been since the days of Homer. The racial type to which Socrates belonged [Alpine] is today the most important, while the Atlanto-Mediterranean, prominent in Greece since the Bronze Age, is still a major factor. It is my personal reaction to the living Greeks that their continuity with their ancestors of the ancient world is remarkable, rather than the opposite." ~ Coon, Carleton S. The Races of Europe. MacMillan, 1939
All ancient skulls found in Mycenaean upper/ruling class tombs in the region of Greece suggest that the ancient inhabitants of the region were of the Mediterranean sub-type of the European Caucasian race, the same is the case with many modern Greeks.
The Günther theory (discredited today), started by German Nazi scientist Hans K. Günther suggests that ancient Greeks were of the Nordic sub-race. Günther himself, however, was very selective to his evidence and ignored proof that suggested otherwise, even when it came from his colleagues. More specifically Angel J. L’s A racial analysis of the ancient Greeks, 1942 later disproved the Günther theory. (Also: Lerna, a pre-classical site in the Argolid, 1971). Modern supporters of the Günther theory use as evidence the fact that some ancient Greek gods and others (ex: Achilles) are described as blonde - a very unscientific approach that we will debunk anyway. The ancient Greek perception of color was different from ours. Achilles is described as “Xanthos”, which in modern Greek does indeed mean blonde, however, it most probably did not in Homer’s time. We can verify this by the fact that when the Greeks met the Celts (A blonde tribe) described them as “White-haired”, which proves that “Xanthos” meant something entirely different. Aristotle himself compared the color to things that we would call brown today, so it probably meant brunet. Another reason why this is an unscientific approach is that blonde =/= Nordic, and there were definitely blonde Mediterranean people, just less common. It is known that Hitler himself did not believe in this theory but let it spread for propaganda purposes. This can be confirmed from his Mein Kampf quote “If the Germans in the ancient times lived in the south, they would have created a civilization similar to that of the Greeks”.
Also, in the context of Anthropology: Composite Greeks: the Ancient and the Modern - the average facial measurements of 16 Greek statues appear identical to the average facial measurements of 16 modern Greek athletes.
In the Balkans, there were mainly two races: The Mediterranean and the Dinaric. The Mediterraneans were forced to remain mainly in the south as the Dinarics migrated from the north. With skull measurements, we have concluded that Ionic & Aeolic Greek skulls are of the Mediterranean sub-type (Ares Poulianos - Anthropology 1968). When it comes to anthropological skull measurements, Doric Greeks are hard to examine, because in their early years they burned the dead (thus, we have no skulls to examine). In their later years, they didn’t - they had however probably mixed with other Greeks too much for us to examine their skulls properly. This would, however, mean that there would be a few Dinaric elements in the surviving skulls, which is not the case. Therefore, we can conclude that they were mainly Mediterranean too.
(Note: there probably were other elements, including Dinaric, in ancient Greeks, just like today. All of which were sub-types of the Caucasian race)
Genetics
“Greeks are some of the earliest contributors of genetic material to the rest of the Europeans as they are one of the oldest populations in Europe” Cavalli-Sforza, Luigi Luca; Menozzi, Paolo; Piazza, Alberto (1996). The History and Geography of Human Genes. Princeton University Press. pp. 255–301. ISBN 0691029059.
“Greeks cluster with other South European (mainly Italians) and North-European populations and are close to the Basques, and FST distances showed that they group with other European and Mediterranean populations” Cavalli-Sforza, Luigi Luca; Menozzi, Paolo; Piazza, Alberto (1996). The History and Geography of Human Genes. Princeton University Press. pp. 255–301. ISBN 0691029059. Bauchet, M; et al. (2007). "Measuring European population stratification with microarray genotype data". Am. J. Hum. Genet. 80: 948–956. doi:10.1086/513477. PMID 17436249.
A 2017 study on the genetic origins of the Minoans and Mycenaeans showed that modern Greeks resemble the Mycenaeans, but with some additional dilution of the early Neolithic ancestry. The results of the study support the idea of genetic continuity between these civilizations and modern Greeks but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations. According to the same study, ancient Mycenaeans mostly carried genes for darker hair and eyes.
Lazaridis, Iosif; et al. (2017). "Genetic origins of the Minoans and Mycenaeans". Nature. 548: 214–218. doi:10.1038/nature23310
Science Magazine, 2 August 2017, "The Greeks really do have near-mythical origins, ancient DNA reveals".
Live Science, 3 August 2017, More than Myth: Ancient DNA Reveals Roots of 1st Greek Civilizations
Katherine Lindemann, DNA analysis traces origins of Minoans and Mycenaeans, ResearchGate, 2nd August 2017
History
People tend to think that Ancient Greeks disappeared after they were conquered by the Romans and popped out of nowhere magically in modern Greece. Looking at it this way, it’s kind of hard to imagine a connection between the two peoples, and it’s understandable. However, that’s not the case. Once the Greeks were conquered by the Romans.. nothing happened. They just became part of another larger state, which, as I said in my epilogue, doesn’t necessarily affect the ethnological composition of the area. That is especially the case with Greece in the Roman empire. Despite the fact that the legions beat the phalanxes and conquered the land of Greece, no major mass migration happened to Greece, therefore the Greek genepool stayed the same until the first third part of the medieval era. In fact, life in Greece wouldn’t be much different from that of classical Greece for centuries to come.
You can find known Greek people from all centuries from ancient Greece to today. That is because the Greek ethnic identity never disappeared and was artificially reconstructed as many might suggest. Greek scholars in the Renaissance - Wikipedia - If the Greek identity was created in 1821 (with the creation of the Greek state) how come there were Greeks four centuries prior to that? List of people from Greece - Wikipedia - As you can see there are notable Greeks from the Middle Ages as well.
Religion
The Greeks were among the first people to start converting to Christianity, and since they were in Eastern Europe and under the “Greek Church” (Non-Roman / Eastern Patriarchate), they eventually became part of the Orthodox Church, which means that modern-day descendants of the Ancient Greeks would be mostly practicing the Orthodox Christian religion today.
Up until the 10th century (yes, the 10th century), there were minorities in the region (especially isolated areas) of Greece in the Byzantine empire that had kept their pagan beliefs and practices, continuity of tradition since the Mycenaean times. Suddenly, the gap between ancient and modern Greeks doesn’t feel so large, does it?
Slavs
The Slavic migrations to Greece happened in the Middle Ages. According to the also disproven and very discredited Fallmerayer theory, the Slavs who came to Greece killed all the Greeks entirely leaving nobody behind and replaced them (?), and the Greeks of minor Asia (Constantinople, Smyrna etc) that had survived the Slavic migration, re-Hellenized the people of mainland Greece. This has not happened ever to any population. Not even the Neanderthals - 2–4% of European DNA is Neanderthal-derived -. Also this theory doesn’t take into account the fact that the Slavs didn’t go to whole of Greece, that they would Speak Slavic in Greece and not Greek today, that Slavs did not go to the coasts or islands or eastern Greece, that Byzantine historians do not mention any massacres from the Slavs - instead what they said is that they formed the infamous “Sklavinies”, or small places where they lived. etc. Generally this is a very discredited theory. Objectively most historians who have studied the matter cringe with such assumptions.
A much lighter version of this theory however is actually true - some Greeks mixed with Slavs, but not too much. According to genetics “Balkan” descent in the average Greek varies from 10–30% depending on the region too. Did you notice that I said Balkan and not Slavic? That is because Slavs are a linguistic group, not an ethnic one. In particular, the ones that came to Greece seemed to have had absorbed Thraco-illyrian and other groups of the Balkans. This can be verified by the skeletons of the only Slavic cemetery found in Greece, near Prespes. The skull shape of the “slavs” is actually of the Mediterranean type. They might have absorbed Greek populations before the mixing with the rest of Greece.
Ottoman Turks
The Turks ruled Greece for centuries, they most definitely mixed.
No. Marriages between Christians and Muslims were illegal in the Ottoman empire, and no Turk converted to Christianity because that meant more taxes and being treated as a second class citizen (and having your male children taken away from you in order to be raised as Ottoman soldiers, more on that later). The opposite did happen though. Many Greeks, in order to avoid the taxes, converted to Islam. As a result a large number of modern day Turks have significant amount of Greek descent. The only time mixing could have happened is by raping women, which even if happened a lot, could not really affect the genepool of the whole population all that much, because the woman would actually have to become pregnant, which by itself is already very unlikely, and the kid would still be only half Turkish, or even less, considering most Ottoman soldiers in campaigns against Greek revolts were Janissaries - males of Greek descent who were raised as Ottoman Turks after being conscripted & forcefully taken away from their Greek Christian parents -.
Arvanites
I read another answer that “the modern Greek state was made up of mostly Albanians, not Greeks”. The guy was probably referring to a bilingual group of people who spoke Greek and Albanian in the Attica region, known as the Arvanites. That’s not the same as saying “Albanian”. Also, Arvanites were a minority in the Greek population, not “most of it” as some like to say in order to promote their agenda. In fact, they were so few that most ethnographical maps ignore them completely. (Just search ethnographical maps of Greece in the Ottoman empire on your favorite search engine and see what I mean.). And still, these Albanians (who migrated to Greece in waves from the 10th to 14th century) were Tosks, not Ghegs. Tosk Albanians (Probably descended from unorganized Greek tribes or the Illyrians) were known to be heavily mixed with the Greeks of Northern Epirus and once they arrived they mixed even more to a point where the Albanian element became significantly weaker. They were probably not even just Tosks, but Tosks & Northern Epirote Greeks (Greek minority in Southern Albanian). Their average skull measurements are more similar to that of Greeks (identical, actually) suggesting they were of Greek descent, but de-Hellenized and linguistically “Albanified” (1)(2). K. Biris has confirmed that when Greek and Albanian populations were mixed, the Albanian language became dominant.(3) Which suggests that they were originally of Greek descent, but fewer when they arrived as well, since they linguistically de-Hellenized other Greeks.
1,2 - N. Rassengeschiechte von Griechenland - Rassengesch. der Meschheit, VI, 1975
3 - K. Biris - Arvanites, 1960
The Arvanites are a very disputed topic, and this is just a theory. Many people believe they were originally Albanian and not Greek. It is important to note, however, that they have mixed too much with the Greeks to be considered Albanian now. Also, if you tell a Greek Arvanite that he is Albanian, he will get quite pissed.
Linguistically
Greek, unlike eg Hebrew, was never revived, as it has been spoken in the region since it was first “created”. People in Greece spoke Greek in the early modern times, the middle ages, the late antiquity Roman times and the ancient times. It is fair to assume that native speakers of any dialect / language derived from Ancient Greek to be cultural descendants of the Ancient Greeks, that however does not seem to please many. “Cultural Descendants?”, you say. “That’s not what I am looking for”. Of course, so let’s get deeper into that.
Modern Greek dialects, all except for one (The endangered Tsakonian dialect) are derived from the Koine Greek dialect. This dialect Hellenized hundreds of thousands of people in the past, which could mean that modern Greeks are descendants of those Hellenized people, and not the Greeks themselves. That’s a very good claim, but can be debunked easily. In areas of Greece were Doric dialects of Greek were spoken people still use some linguistic features that are actually derived from the Doric dialects. For example you might hear the Doric “Zesta” (warmth) instead of the Ionic Attic “Zesti” of standard Greek. That suggests that previously the same people spoke a different dialect of Greek, and not a non Greek language. Such linguistic evidence can be found all over Greek. It was easy for them to adopt a new Greek dialect since they already spoke Greek. Hellenized people who previously spoke another language almost never had Greek as their first language, and many had forgotten it after a few generations, so only a small percentage of modern Greek DNA comes from those who were linguistically Hellenized
The Slavophones Greeks of northern Greece were a bilingual group of people who spoke Greek as a second language and a Slavic idiom as a first daily-talk language. That Slavic idiom has many Greek words - Estimates reach more than 52% (changes depending the area), and was mostly spoken in the mountains, away from other Greek speakers which means that this vocabulary was derived from the previous language they spoke - Greek. Many of them adopted Slavic to avoid Ottoman discrimination against Greek speakers, others because they were merchants and mostly traded with northern Slavs etc. They usually lived near other Slavs (Which is why they were linguistically “Slavified”) but had different national awareness which can be confirmed by the many wars and conflicts they had (most notably the Macedonian struggle). They attended different Churches (especially after the creation of the Bulgarian Exarchia) etc. Of course these people have higher Balkan Thraco-Illyrian blood from mixing but their Greek descent is stronger, which has been confirmed by DNA studies.
Conclusion
Greeks, just like everyone else, have actually mixed with foreign populations. However that mixing was certainly not enough to break the strong connection between modern and ancient Greeks. It’s important to know that Greeks are subdivided in to many groups that live in different areas. Islander Greeks are probably the most similar to ancient ones, however they probably went through incest as well, especially in smaller islands. Greeks from the western seashores of Anatolia, like Greeks from Smyrna & Constantinople are also very similar to ancient Greeks, because there were no other Christians in the area to mix with. Greeks from the southern Black Sea shores seem to have high Caucasian Armenoid influence, those from Cappadocia along with Greek, also have some descent from the ancient Caucasian Anatolian tribes (who were Indo-European, and probably similar to the Greeks as well). Those from Cyprus have southern influences and those from the very North have some Balkan influence.