Most Greeks speak the Greek language, an independent branch of the Indo-European languages, with its closest relations possibly being Armenian (see Graeco-Armenian) or the Indo-Iranian languages (see Graeco-Aryan). It has the longest documented history of any living language and Greek literature has a continuous history of over 2,500 years. The oldest inscriptions in Greek are in the Linear B script, dated as far back as 1450 BC. Following the Greek Dark Ages, from which written records are absent, the Greek alphabet appears in the 9th–8th century BC. The Greek alphabet derived from the Phoenician alphabet, and in turn became the parent alphabet of the Latin, Cyrillic, and several other alphabets. The earliest Greek literary works are the Homeric epics, variously dated from the 8th to the 6th century BC. Notable scientific and mathematical works include Euclid's Elements, Ptolemy's Almagest, and others. The New Testament was originally written in Koine Greek.
Greek demonstrates several linguistic features that are shared with other Balkan languages, such as Albanian, Bulgarian and Eastern Romance languages (see Balkan sprachbund), and has absorbed many foreign words, primarily of Western European and Turkish origin. Because of the movements of Philhellenism and the Diafotismos in the 19th century, which emphasized the modern Greeks' ancient heritage, these foreign influences were excluded from official use via the creation of Katharevousa, a somewhat artificial form of Greek purged of all foreign influence and words, as the official language of the Greek state. In 1976, however, the Hellenic Parliament voted to make the spoken Dimotiki the official language, making Katharevousa obsolete.
Modern Greek has, in addition to Standard Modern Greek or Dimotiki, a wide variety of dialects of varying levels of mutual intelligibility, including Cypriot, Pontic, Cappadocian, Griko and Tsakonian (the only surviving representative of ancient Doric Greek). Yevanic is the language of the Romaniotes, and survives in small communities in Greece, New York and Israel. In addition to Greek, many Greek citizens in Greece and the diaspora are bilingual in other languages such as English, Arvanitika/Albanian, Aromanian, Megleno-Romanian, Macedonian Slavic, Russian and Turkish.
Most Greeks are Christians, belonging to the Greek Orthodox Church. During the first centuries after Jesus Christ, the New Testament was originally written in Koine Greek, which remains the liturgical language of the Greek Orthodox Church, and most of the early Christians and Church Fathers were Greek-speaking. There are small groups of ethnic Greeks adhering to other Christian denominations like Greek Catholics, Greek Evangelicals, Pentecostals, and groups adhering to other religions including Romaniot and Sephardic Jews and Greek Muslims. About 2,000 Greeks are members of Hellenic Polytheistic Reconstructionism congregations.
Greek-speaking Muslims live mainly outside Greece in the contemporary era. There are both Christian and Muslim Greek-speaking communities in Lebanon and Syria, while in the Pontus region of Turkey there is a large community of indeterminate size who were spared from the population exchange because of their religious affiliation.
Greek art has a long and varied history. Greeks have contributed to the visual, literary and performing arts. In the West, classical Greek art was influential in shaping the Roman and later the modern Western artistic heritage. Following the Renaissance in Europe, the humanist aesthetic and the high technical standards of Greek art inspired generations of European artists. Well into the 19th century, the classical tradition derived from Greece played an important role in the art of the Western world. In the East, Alexander the Great's conquests initiated several centuries of exchange between Greek, Central Asian and Indian cultures, resulting in Indo-Greek and Greco-Buddhist art, whose influence reached as far as Japan.
Byzantine Greek art, which grew from the Hellenistic classical art and adapted the pagan motifs in the service of Christianity, provided a stimulus to the art of many nations. Its influences can be traced from Venice in the West to Kazakhstan in the East. In turn, Greek art was influenced by eastern civilizations (i.e. Egypt, Persia, etc.) during various periods of its history.
Notable modern Greek artists include the major Renaissance painter Dominikos Theotokopoulos (El Greco), Nikolaos Gyzis, Nikiphoros Lytras, Konstantinos Volanakis, Theodoros Vryzakis, Georgios Jakobides, Thalia Flora-Karavia, Yannis Tsarouchis, Nikos Engonopoulos, Périclès Pantazis, Theophilos, Kostas Andreou, Jannis Kounellis, sculptors such as Leonidas Drosis, Georgios Bonanos, Yannoulis Chalepas, Athanasios Apartis, Konstantinos Dimitriadis and Joannis Avramidis, conductor Dimitri Mitropoulos, soprano Maria Callas, composers such as Mikis Theodorakis, Nikos Skalkottas, Nikolaos Mantzaros, Spyridon Samaras, Manolis Kalomiris, Iannis Xenakis, Manos Hatzidakis, Manos Loïzos, Yanni and Vangelis, the masters of rebetiko Markos Vamvakaris and Vassilis Tsitsanis, and singers such as Giorgos Dalaras, Haris Alexiou, Sotiria Bellou, Nana Mouskouri, Vicky Leandros and Demis Roussos. Poets such as Andreas Kalvos, Athanasios Christopoulos, Kostis Palamas, the writer of Hymn to Liberty Dionysios Solomos, Angelos Sikelianos, Kostas Karyotakis, Maria Polydouri, Yannis Ritsos, Kostas Varnalis, Nikos Kavvadias, Andreas Embirikos and Kiki Dimoula. Constantine P. Cavafy and Nobel laureates Giorgos Seferis and Odysseas Elytis are among the most important poets of the 20th century. Novel is also represented by Alexandros Papadiamantis, Emmanuel Rhoides, Ion Dragoumis, Nikos Kazantzakis, Penelope Delta, Stratis Myrivilis, Vassilis Vassilikos and Petros Markaris, while notable playwrights include the Cretan Renaissance poets Georgios Chortatzis and Vincenzos Cornaros, such as Gregorios Xenopoulos and Iakovos Kambanellis.
Notable cinema or theatre actors include Marika Kotopouli, Melina Mercouri, Ellie Lambeti, Academy Award winner Katina Paxinou, Alexis Minotis, Dimitris Horn, Thanasis Veggos, Manos Katrakis and Irene Papas. Alekos Sakellarios, Karolos Koun, Vasilis Georgiadis, Kostas Gavras, Michael Cacoyannis, Giannis Dalianidis, Nikos Koundouros and Theo Angelopoulos are among the most important directors.
Among the most significant modern-era architects are Stamatios Kleanthis, Lysandros Kaftanzoglou, Anastasios Metaxas, Panagis Kalkos, Anastasios Orlandos, the naturalized Greek Ernst Ziller, Dimitris Pikionis and urban planners Stamatis Voulgaris and George Candilis.
The Greeks of the Classical and Hellenistic eras made seminal contributions to science and philosophy, laying the foundations of several western scientific traditions, such as astronomy, geography, historiography, mathematics, medicine, philosophy and political science. The scholarly tradition of the Greek academies was maintained during Roman times with several academic institutions in Constantinople, Antioch, Alexandria and other centers of Greek learning, while Byzantine science was essentially a continuation of classical science. Greeks have a long tradition of valuing and investing in paideia (education). Paideia was one of the highest societal values in the Greek and Hellenistic world while the first European institution described as a university was founded in 5th century Constantinople and operated in various incarnations until the city's fall to the Ottomans in 1453. The University of Constantinople was Christian Europe's first secular institution of higher learning since no theological subjects were taught, and considering the original meaning of the world university as a corporation of students, the world's first university as well.
As of 2007, Greece had the eighth highest percentage of tertiary enrollment in the world (with the percentages for female students being higher than for male) while Greeks of the Diaspora are equally active in the field of education. Hundreds of thousands of Greek students attend western universities every year while the faculty lists of leading Western universities contain a striking number of Greek names. Notable Greek scientists of modern times include Indologist Dimitrios Galanos, Dr Georgios Papanicolaou (inventor of the Pap test), mathematician Constantin Carathéodory, archaeologists Manolis Andronikos, Valerios Stais, Spyridon Marinatos and Ioannis Svoronos, computer scientists Michael Dertouzos, John Argyris, Nicholas Negroponte, Joseph Sifakis (2007 Turing Award, the "Nobel Prize" of Computer Science), Christos Papadimitriou (2002 Knuth Prize, 2012 Gödel Prize) and Mihalis Yannakakis (2005 Knuth Prize), physicists Achilles Papapetrou, Dimitri Nanopoulos and John Iliopoulos (2007 Dirac Prize for his contributions on the physics of the charm quark, a major contribution to the birth of the Standard Model, the modern theory of Elementary Particles), astronomer Eugenios Antoniadis, biologist Fotis Kafatos, botanist Theodoros Orphanides, economist Xenophon Zolotas, linguist Yiannis Psycharis, historians Constantine Paparrigopoulos and Helene Glykatzi Ahrweiler and political scientists Nicos Poulantzas and Cornelius Castoriadis.
Significant engineers and automobile designers include Nikolas Tombazis, Alec Issigonis and Andreas Zapatinas.
The most widely used symbol is the flag of Greece, which features nine equal horizontal stripes of blue alternating with white representing the nine syllables of the Greek national motto Eleftheria i Thanatos (Freedom or Death), which was the motto of the Greek War of Independence. The blue square in the upper hoist-side corner bears a white cross, which represents Greek Orthodoxy. The Greek flag is widely used by the Greek Cypriots, although Cyprus has officially adopted a neutral flag to ease ethnic tensions with the Turkish Cypriot minority (see flag of Cyprus).
The pre-1978 (and first) flag of Greece, which features a Greek cross (crux immissa quadrata) on a blue background, is widely used as an alternative to the official flag, and they are often flown together. The national emblem of Greece features a blue escutcheon with a white cross surrounded by two laurel branches. A common design involves the current flag of Greece and the pre-1978 flag of Greece with crossed flagpoles and the national emblem placed in front.
Another highly recognizable and popular Greek symbol is the double-headed eagle, the imperial emblem of the last dynasty of the Eastern Roman Empire and a common symbol in Asia Minor and, later, Eastern Europe. It is not part of the modern Greek flag or coat-of-arms, although it is officially the insignia of the Greek Army and the flag of the Church of Greece. It had been incorporated in the Greek coat of arms between 1925 and 1926.
Classical Athens is considered the birthplace of Democracy. The term appeared in the 5th century BC to denote the political systems then existing in Greek city-states, notably Athens, to mean "rule of the people", in contrast to aristocracy (ἀριστοκρατία, aristokratía), meaning "rule by an excellent elite", and to oligarchy. While theoretically these definitions are in opposition, in practice the distinction has been blurred historically. Led by Cleisthenes, Athenians established what is generally held as the first democracy in 508–507 BC, which took gradually the form of a direct democracy. The democratic form of government declined during the Hellenistic and Roman eras, only to be revived as an interest in Western Europe during the early modern period.
The European enlightenment and the democratic, liberal and nationalistic ideas of the French Revolution was a crucial factor to the outbreak of the Greek War of Independence and the establishment of the modern Greek state.
Notable modern Greek politicians include Ioannis Kapodistrias, founder of the First Hellenic Republic, reformist Charilaos Trikoupis, Eleftherios Venizelos, who marked the shape of modern Greece, social democrats Georgios Papandreou and Alexandros Papanastasiou, Konstantinos Karamanlis, founder of the Third Hellenic Republic, and socialist Andreas Papandreou.
Greek surnames began to appear in the 9th and 10th century, at first among ruling families, eventually supplanting the ancient tradition of using the father's name as disambiguator. Nevertheless, Greek surnames are most commonly patronymics, such those ending in the suffix -opoulos or -ides, while others derive from trade professions, physical characteristics, or a location such as a town, village, or monastery. Commonly, Greek male surnames end in -s, which is the common ending for Greek masculine proper nouns in the nominative case. Occasionally (especially in Cyprus), some surnames end in -ou, indicating the genitive case of a patronymic name. Many surnames end in suffixes that are associated with a particular region, such as -akis (Crete), -eas or -akos (Mani Peninsula), -atos (island of Cephalonia), -ellis (island of Lesbos) and so forth. In addition to a Greek origin, some surnames have Turkish or Latin/Italian origin, especially among Greeks from Asia Minor and the Ionian Islands, respectively. Female surnames end in a vowel and are usually the genitive form of the corresponding males surname, although this usage is not followed in the diaspora, where the male version of the surname is generally used.
With respect to personal names, the two main influences are Christianity and classical Hellenism; ancient Greek nomenclatures were never forgotten but have become more widely bestowed from the 18th century onwards. As in antiquity, children are customarily named after their grandparents, with the first born male child named after the paternal grandfather, the second male child after the maternal grandfather, and similarly for female children. Personal names are often familiarized by a diminutive suffix, such as -akis for male names and -itsa or -oula for female names. Greeks generally do not use middle names, instead using the genitive of the father's first name as a middle name. This usage has been passed on to the Russians and other East Slavs (otchestvo).
The traditional Greek homelands have been the Greek peninsula and the Aegean Sea, Southern Italy (Magna Graecia), the Black Sea, the Ionian coasts of Asia Minor and the islands of Cyprus and Sicily. In Plato's Phaidon, Socrates remarks, "we (Greeks) live around a sea like frogs around a pond" when describing to his friends the Greek cities of the Aegean. This image is attested by the map of the Old Greek Diaspora, which corresponded to the Greek world until the creation of the Greek state in 1832. The sea and trade were natural outlets for Greeks since the Greek peninsula is mostly rocky and does not offer good prospects for agriculture.
Notable Greek seafarers include people such as Pytheas of Massalia who sailed to Great Britain, Euthymenes who sailed to Africa, Scylax of Caryanda who sailed to India, the navarch of Alexander the Great Nearchus, Megasthenes, explorer of India, later the 6th century merchant and monk Cosmas Indicopleustes (Cosmas who sailed to India), and the explorer of the Northwestern Passage Ioannis Fokas also known as Juan de Fuca. In later times, the Byzantine Greeks plied the sea-lanes of the Mediterranean and controlled trade until an embargo imposed by the Byzantine emperor on trade with the Caliphate opened the door for the later Italian pre-eminence in trade. Panayotis Potagos was another explorer of modern times who was the first to reach Mbomu and Uele River from the north.
The Greek shipping tradition recovered during the late Ottoman rule (especially after the Treaty of Küçük Kaynarca and during the Napoleonic Wars), when a substantial merchant middle class developed, which played an important part in the Greek War of Independence. Today, Greek shipping continues to prosper to the extent that Greece has one of the largest merchant fleets in the world, while many more ships under Greek ownership fly flags of convenience. The most notable shipping magnate of the 20th century was Aristotle Onassis, others being Yiannis Latsis, Stavros G. Livanos, and Stavros Niarchos.
Genetic studies using multiple autosomal gene markers, Y chromosomal DNA haplogroup analysis and mitochondrial gene markers (mtDNA) show that Greeks share similar backgrounds as the rest of the Europeans and especially Southern Europeans (Italians and southern Balkan populations such as Albanians, Slavic Macedonians and Romanians). According to the studies using multiple autosomal gene markers, 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. A study in 2008 showed that Greeks are genetically closest to Italians and Romanians and another 2008 study showed that they are close to Italians, Albanians, Romanians and southern Balkan Slavs. A 2003 study showed that 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, especially with Italians (−0.0001) and Tuscans (0.0005).
Y DNA studies show that Greeks cluster with other Europeans and that they carry some of the oldest Y haplogroups in Europe, in particular the J2 haplogroup (and other J subhaplogroups) and E haplogroups, which are genetic markers denoting early farmers. The Y-chromosome lineage E-V13 appears to have originated in Greece or the southern Balkans and is high in Greeks as well as in Albanians, southern Italians and southern Slavs. E-V13 is also found in Corsicans and Provencals, where an admixture analysis estimated that 17% of the Y-chromosomes of Provence may be attributed to Greek colonization, and is also found at low frequencies on the Anatolian mainland. These results suggest that E-V13 may trace the demographic and socio-cultural impact of Greek colonization in Mediterranean Europe, a contribution that appears to be considerably larger than that of a Neolithic pioneer colonization. A study in 2008 showed that Greek regional samples from the mainland cluster with those from the Balkans, principally Albanians while Cretan Greeks cluster with the central Mediterranean and Eastern Mediterranean samples. Greek signature DNA influence can be seen in Southern Italy and Sicily, where the genetic contribution of Greek chromosomes to the Sicilian gene pool is estimated to be about 37%, and the Southern Balkans, primarily Albania. Di Gaetano et al. also note that the genetic links analysed in their findings "shows that Sicily and southeastern Europe, especially Greece and Albania, share a common background."
Studies using mitochondrial DNA gene markers (mtDNA) showed that Greeks group with other Mediterranean European populations and principal component analysis (PCA) confirmed the low genetic distance between Greeks and Italians and also revealed a cline of genes with highest frequencies in the Balkans and Southern Italy, spreading to lowest levels in Britain and the Basque country, which Cavalli-Sforza associates it with "the Greek expansion, which reached its peak in historical times around 1000 and 500 BC but which certainly began earlier".
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. In an interview, the study's author, Harvard University geneticist Iosif Lazaridis, precised "that all three Bronze Age groups (Minoans, Mycenaeans, and Bronze Age southwestern Anatolians) trace most of their ancestry from the earlier Neolithic populations that were very similar in Greece and western Anatolia. But, they also had some ancestry from the 'east', related to populations of the Caucasus and Iran" as well as "some ancestry from the "north", related to hunter-gatherers of eastern Europe and Siberia and also to the Bronze Age people of the steppe. We could also compare the Mycenaeans—again, the first speakers of the Greek language—to modern people from Greece who are very similar to them, but with lower early Neolithic ancestry", and argues that "some had theorized that the Minoan and Mycenaean civilizations were influenced both culturally and genetically by the old civilizations of the Levant and Egypt, but there is no quantifiable genetic influence".
A study from 2013 for prediction of hair and eye colour from DNA of the Greek people showed that the self-reported phenotype frequencies according to hair and eye colour categories was as follows: 119 individuals – hair colour, 11 blond, 45 dark blond/light brown, 49 dark brown, 3 brown red/auburn and 11 had black hair; eye colour, 13 with blue, 15 with intermediate (green, heterochromia) and 91 had brown eye colour.
Another study from 2012 included 150 dental school students from the University of Athens, and the results of the study showed that light hair colour (blonde/light ash brown) was predominant in 10.7% of the students. 36% had medium hair colour (light brown/medium darkest brown), 32% had darkest brown and 21% black (15.3 off black, 6% midnight black). In conclusion, the hair colour of young Greeks are mostly brown, ranging from light to dark brown with significant minorities having black and blonde hair. The same study also showed that the eye colour of the students was 14.6% blue/green, 28% medium (light brown) and 57.4% dark brown.
The history of the Greek people is closely associated with the history of Greece, Cyprus, Constantinople, Asia Minor and the Black Sea. During the Ottoman rule of Greece, a number of Greek enclaves around the Mediterranean were cut off from the core, notably in Southern Italy, the Caucasus, Syria and Egypt. By the early 20th century, over half of the overall Greek-speaking population was settled in Asia Minor (now Turkey), while later that century a huge wave of migration to the United States, Australia, Canada and elsewhere created the modern Greek diaspora.