"The most severe human differences are shown in that what they have most in common."
(B. Cendrase)
At the moment that I am writing this text I am still studying the Indo-European culture and language so I do not claim to be a professional, this is merely an enumeration of information and some thoughts and speculation, because of the lack of archeological evidence it is difficult to say anything definitive about the Indo-Europeanization and it is unknown from where the Indo-European culture was spread over the western world or from which culture(s) it originated, but the fact is that it deeply influenced many peoples and that many aspects of the Indo-European culture, religion, and language were taken over in an area that stretched from Europe to as far as India.
Misconceptions:
There are many theories about who the Indo-Europeans were; one of them states that the Indo-Europeans were some kind of "master-race" from Atlantis or Ultima Thule who founded all the great civilizations of mankind and almost replaced the original populations of many countries, which would also explain the high amount of Indo-European influences in the present day cultures and languages, this theory is completely incorrect and highly outdated but during world war 2 the nazis were firm believers of it and even sent an expedition to India to find traces of their illusionary master-race.
In reality the Indo-Europeans were probably not even a single people but rather a group of different peoples who all had the same (Indo-European) culture and language, their migration brought their culture and language to other peoples and lands where it was adopted into the native cultures, in many cases it was probably just a migration of culture and language that may have been caused by the high cultural en political influence of the Indo-European peoples.
A good example from our own period is the U.S.A.; this country is so influential that many aspects of its identity are being adopted by those around them and mixed with the native ways; their moral values, their democratic ideals, their language, etc.
For instance there is a whole ocean between America and the country where I live (the Netherlands) but still many people here celebrate Halloween, eat at McDonalds, and give eachother presents at Valentine's day, customs such as this are mixed with native customs like Easter fires and Midwinter celebrations, over 80% of the population here can speak English and many English words are even being permanently adopted into our language, something similar may have happened during the Indo-European period.
Origins:
It is unknown where the cradle of the Indo-European culture was situated but there are many theories about this, most of them agree that it was somewhere around the Black sea but other theories suggest areas near the Caspian sea or the Baltic sea, this quest for the Indo-European homeland is called "die Urheimatsfrage" (the question of the ancient homeland).
We can only speculate about the origins of the Indo-European culture but the Kurgan culture in Russia and the Ukraine is often mentioned as one of the first Indo-European cultures, the Corded Ware culture (also known as the Battle-axe culture) is believed to have originated from the Kurgan culture and was probably one of the first Indo-European cultures that expanded westwards into Europe, but this is still debated.
The Indo-European cultures also moved south- and eastwards, we know a bit more about this tribes than the ones that invaded Europe so perhaps by looking at them we can also learn more about their Indo-European relatives in Europe.
Indo-European invasions in India:
The most famous Indo-European tribes are the Dorians (Greece and the Balkans), Hittites (the Middle East), Tocharians (western China), and the Aryans (India), because of the nazis there are many misconceptions about this last group so I shall tell a little bit more about them.
The Aryans were an Indo-European people who called themselves "Arya", which means "noblemen" in Sanskrit, they are believed to have originated from the Wolga area in Russia and from there they went to Turkey and later Iran where they stayed for some time, eventually they moved towards the Kabul river and around 1500BC they conquered the Indus valley, from there they migrated into the direction of the Ganges and founded an empire in what is now Pakistan and northern India.
The original inhabitants were quickly defeated because the Arya had a more advanced army; they were good archers and swordsmen and they used a chariot with two archers that was feared by their enemies, especially in India because horses were unknown there, many other Indo-European tribes also used horses and were more mobile because of that, which may have given their armies an advantage over their enemies.
Before the Indo-European invasion India was a flourishing civilization with cities of over 50.000 inhabitants, but the Arya (who proudly called themselves "the citydestroyers" in their veda's) left most of them in ruins and slaughtered their inhabitants.
Everywhere they came they introduced their language Sanskrit and in this language the veda's were written down, this were laws but also heroic poems, the word "veda" means "to know" in Sanskrit and is related to other Indo-European words like for instance Germanic "witan" (to know), in the Dutch language laws are called "wetten" (knowings), a word that may have also been introduced during the Indo-European period.
The Arya also brought a new religion with them that can be considered the direct ancestor of Hinduism (Buddhism is a later variation of Hinduism according to the views of Buddha), the laws were created by the brahmans (priests) who formed the upper class and were even more important than kings.
In the new society people were no longer equal and women became the posession of their husbands, everybody was also fitted into a caste, according to the Hinduistic religion the god Brahma created 4 castes, a parallel to this (Indo-European?) belief can be found in Germanic mythology where the god Rigr creates 3 castes, the castes of Hindu society consisted of the brahmans (priests), the kshatriyas (warriors, warlords, and kings), the vaisyas (farmers and traders), and the sudras (workers and craftsmen), under the sudras came the slaves but they were considered to be so low that they didn't even got their own caste.
Marrying someone from another caste was forbidden and it was believed that being (re)born in a lower caste was a punishment for crimes committed in a past life, the caste system lasted for a very long time and was eventually abolished in the 20th century.
The Arya also believed that their white skincolour was a sign of their superiourity over the native inhabitants of India, who had a dark skincolour and were the descendants of Africans who had settled in India thousands of years ago, the Dravidians in southern India are their descendants.
The Arya saw the native people as inferiour to them and called them "flatnoses" or "dasyus" ("monsters" or "barbarians"), the word "varna" (colour) was eventually even used as an alternative word for "caste" and the brahmans created racial laws that prohibited any mixing between the Arya and the natives.
Because of this intolerant ideas the nazis had a great interest in the historical Arya/Aryans and they adopted their name for people of Nordic origin, Heinrich Himmler (the leader of the SS) even carried a copy of the Bhagavadhgita and sent scientists to the Himalayans to find lost civilizations of "übermenschen", the nazis also adapted the Hindu caste system to their own doctrine.
These days the word "Aryan" has been completely stigmatized by the nazis but the truth is that the Aryans weren't so "Aryan" at all, historical depictions of them show tanned darkhaired people who may have had a lighter skin than the native people of India but they were definitely not the blond blue-eyed superhumans that the nazis believed them to be.
Whether or not the Arya should be considered a "good" or a "bad" people is irrelevant here and should be left to the opinion of the reader, however, what we know about them does give us some more information about the culture of the other Indo-European peoples, though we should not simply lump all Indo-European peoples together because there were also many differences between them.
Indo-European invasions in Greece:
Another interesting Indo-European people are the Dorians, who invaded Greece around 1200BC and conquered the Bronze Age Mycenean cultures, they originally came from the north and quickly dominated most of mainland Greece, after that they crossed the Peloponnesian mountains and eventually reached the Greek islands, it is unknown why they were so successful but their superiour weapons (iron swords) probably played a role as well as their typically Indo-European warrior-culture.
In the centuries thereafter the Dorian influence grew and their colonies could be found in southern Italy, the Crimean, and western Asia Minor, the most important Dorian city became Sparta.
In most places the Dorians merged with the native people but in Sparta, Crete, and some other areas the people were ruled by a Dorian warrior-elite to whom the native people were nothing more than slaves, in Laconia (the area ruled by Sparta) this people were called the "helots", the helots were farmers who provided the Spartans with food, who in return kept a close eye on them, though mainly because the Spartans feared a helot rebellion, eventually democracy was introduced in Greece which gave the helots more rights, though voting rights in the Greek "democracy" were still limited to the men of noble origin, the second class (above the helots) in Sparta were the perioeci, who were foreigners doing the work that was too high for the helots and too low for the Spartans, the upper class were the spartiate, or native Spartans.
Spartan society was so hard that it has become proverbial in many modern languages; when a newborn child showed signs of weakness it was thrown off the cliffs and there was hardly any place for luxury in the militaristic Spartan society either, men were trained to become soldiers (called hoplites) and if they went somewhere to fight they would either return victorious or they would not return at all, soldiers who returned while their comrades had fallen on the battlefield lost all status and respect, therefor the Spartans would even continue to fight when their situation was completely hopeless.
Their attitude did gain the Spartans many victories though; at the battle of Plataea the Spartans managed to defeat a Persian army that was twice as big as theirs and at Thermopylae king Leonidas with his Spartan hoplites and Greek allies even fought a Persian army of at least 3.000.000 men, although all 300 Spartans, their king Leonidas, and over 2000 other Greek warriors were killed they never retreated and managed to kill an estimated 20.000 Persians before they fell, although they lost the battle they won the war because they had bought the Greeks some precious time to organize their resistance, eventually the Persians were defeated at the battle of Salamis.
Like I have mentioned before the Indo-European peoples had many differences but by comparing them we can see that they also had many similarities; a patriarchal society that was more or less based on caste system, a warrior-elite, superiour armies, and closely related mythologies and languages.
Language:
The Indo-European languages have many words in common, for instance the English word "milk" is indirectly derived from Proto-Germanic *meluk which is derived from Proto-Indo-European *melg, the word can also be found in many other Indo-European languages, for instance in Sanskrit (melg) and in Tocharian (malk).
In many languages the influences from the Indo-European language were so high that Indo-European words eventually formed the majority of the language, though their original pronounciation was often changed to that of the native language, to give another example from my own country; the English word "weed" has been adopted into the Dutch language as "wiet"; the meaning is still the same only then with a different spelling and a Dutch pronounciation.
The most important Indo-European language groups are; Indo-Iranian, Tocharian (extinct), Illyrian (extinct except for Albanian), Baltic, Slavic, Germanic, Celtic, Italic, Greek, Armenian, Thracian (extinct), Dacian (extinct), Phrygian, and Anatolian (extinct).
Mythology and religion:
Many of the similarities between the beliefs, gods, and myths of the Indo-European peoples may be of Proto-Indo-European origin but we must not forget that there are also many universal conceptions that humans everywhere around the world believe in, furthermore some of the myths may be based on real events that influenced many peoples around the world, for instance the Great Flood myths may have been caused by a real flood that was later exaggerated to mythic proportions, some people even believe that certain mythological similarities contain a universal truth that originates from the beginning of humanity when gods still walked the earth, but of course this is pure speculation.
Many of the similarities may have also been caused by neighbouring cultures influencing eachother, the Romans for instance equaled their gods to those of other peoples and mixed them with their mythology.
Many texts that deal with the Indo-Europeans also have small lists where the gods of various Indo-European pantheons are being compared or even equaled to eachother, these days this is no longer accepted because most gods of the old pantheons probably descended from the native culture and were only influenced by the Indo-European religion which may have changed their names or some of their characteristics, therefor I shall not create such a list, it would be insulting to a Christian to say that his god Jahweh is the same as Allah or Amon-Ra, so I will also refrain from comparing Wodan to Zeus or Thunar to Mars.
Although many similarities between the religions and mythologies of various cultures can be explained as mutual influences or universal ideas it is believed that some of these similarities are indeed of Indo-European origin, for instance there are similarities between the Fates (Romans) and the Norns (Germanic), the works of Heracles (Greek) and the works of Brian (Celtic), Kaďn killing his brother Abel (Christian) and Remus killing his brother Romulus (Roman), the headwound of Conchobhar (Celtic) and the headwound of Thor (Germanic), Diarmuid (Celtic) and Adonis (Greek), Gilgamesj with the courtesan (Sumerian) and Adam and Eve (Christian), Fraoch (Celtic) and Beowulf (Germanic), the talking head of Lomna (Celtic) and the talking head of Mimir (Germanic), the invisible making cloak of Angus (Celtic) and the invisible making cloak/tarnkappe of Siegfried (Germanic), etc.
Some other examples of universal mythological aspects are:
Demonic snakes:
Hindu mythology: the demonic snake Vrtra was defeated by the god Indra.
Buddist mythology: tells about a dragon serpent named Naga.
Germanic mythology: the demonic snake Jormungandr will be defeated by the god Thor at Ragnarök.
Australian Aboriginal mythology: the sisters Wagilak bathed in the well of the snake Yurlunggor, when the oldest sister contaminated the water with her menstruation blood the snake ate the sisters and their children and caused a great flood.
Holy syllables:
Hindu mythology: during prayers the Hindus sing the holy syllable "om".
Islamic mythology: in Islam "ameen" is used as a holy syllable.
Christian mythology: prayers are ended with "amen".
Battle between father and son:
Germanic mythology: the Hildebrandslied tells about how two armies faced eachother in the field, one was lead by Hildebrand and the other by his son Hadubrand.
Hildebrand told Hadubrand that he was his son and that they shouldn't fight, but Hadubrand didn't believe him because he was told that his father died long ago, the two men fought and Hildebrand had to kill his own son.
Celtic mythology: the hero Cu Chulainn met his son Conlai whom he hadn't seen for years, Conlai challenged him to a duel and refused to tell his name, after a long fight Cu Chulainn killed his son and to his grief he then found out that the man he had killed but his own forgotten son.
Persian mythology: the hero Rustam fought with his forgotten son Sohrab and killed him.
Understanding the language of animals:
Germanic mythology: Sigurd/Siegfried who roasted the heart of the dragon Fafnir, burned his finger, put it in his mouth, and then received the ability to understand birds.
Celtic mythology: Fionn mac Cumhaill (Finn McCool) who baked the salmon of knowledge, burned his finger, put it in his mouth, and then received the ability to understand animals.
The holy trinity:
Egyptian mythology: Osiris, Isia, and Horus.
Hindu mythology: Brahma, Vishnu, and Shiva.
Greek mythology: Zeus, Poseidon, and Hades.
Zorastrian mythology: Ormuzd, Mithras, and Ahriman.
Roman mythology: Jupiter, Neptunus, and Pluto.
Christian mythology: the Father, the Son, and the Holy Ghost.
Celtic mythology: Hu, Ceridwen, and Crierwy.
Germanic mythology: Wodan, Frea, and Thunar / Odin, Vili, and Vé / Ingaevones, Istaevones, and Herminones.
Hellhounds:
Greek mythology: the three-headed hellhound Cerberus guarding Hades.
Germanic mythology: the four-eyed hellhound Garm who guards the gate to Hel and will fight with Tyr on Ragnarök.
Hindu mythology: the afterlive was guarded by the four-eyed dogs of Yama, the king of the dead.
Egyptian mythology: Anubis, the god of the embalming of the dead, has the head of a hound or jackal.
Celtic mythology: the hounds of the afterlife Annwn.
Christian mythology: the Angel of Death can only be seen by dogs.
The invulnerable hero:
Germanic mythology: the god Balder was invulnerable to everything in the universe except mistletoe, so he was killed with a mistletoe arrow.
The hero Siegfried was also invulnerable except for his back, so he was killed from behind.
Greek mythology: the hero Achilles was invulnerable except for his heel, an arrow struck his heel and he died.
Ossetic mythology: the god Sosland was invulnerable but was killed by Syrdon through treachery.
The universe being created from the body of a primeval being:
Hindu mythology: in the Visjnu-purana it is described how Prajapati created the animals from his body and that his hair became vegetation.
Another Hindu myth tells how the universe was partially created from the body of a primeval being called Purusha.
Chinese mythology: the Tsju yi ki mentions that the first being (P'an-ku) was born out of an egg-shaped chaos in which heaven and earth were mixed, eventually both were placed in order and Yang created the heavens and Yin the earth, when P'an-ku died his head became a holy mountaintop, his eyes the sun and moon, his fat the rivers and seas, and his hair became the trees and other vegetation.
Babylonian mythology: the god Marduk killed the dragon Tiamat and used its body to create the world; from the upper body he created the heavens, from the lower body the earth, and from the eye sockets the rivers Eufrates and Tigris flowed.
Tiamats tail became a plug in the earth that prevented the waters of Apsu (the world ocean) to flood the land, strong columns separated heaven and earth.
Germanic mythology: the Prose Edda mentions that the gods killed the giant Ymir and created the world from his body and the seas from his blood, his bones became mountains and his hair the trees.
Celtic mythology: a giant named Heaven was killed by one of his own sons, from his skull they made the firmament and from his blood the oceans.
Inuit mythology: the Inupiaq in Alaska believe that "Great Raven", a primeval being created by a shaman, killed a whale and created the earth from its body.
Originating from a wolf:
Roman mythology: the legendary twins Remus and Romulus who founded Rome were raised by a she-wolf.
Turkish mythology: a boy was raised by a she-wolf called Kök Böri (Blue Wolf), he got ten children with her from whom the Turkish people originate, the Huns had a similar myth.
Mongol mythology: a blue-gray wolf begot children with his wife (who was a fallow deer) near the Onon river, from their son the Mongols originate.
The abandoned child(ren):
Christian mythology: the Bible tells about Mozes who was hidden for the Pharao and laid in a basket in the river Nile where he was later found.
Roman mythology: Remus and Romulus were laid in a cradle and thrown into the river Tiber by order of king Amulius, they were later found and raised by a she-wolf.
The Great Flood:
Christian mythology: God was angry about the sins of humanity so he asked Noah to build an ark and collect two individuals of each species aboard, he then caused a great flood to destroy all life on earth. (Genesis 6:7, 7:17, and 7:19)
Islamic mythology: this story is of Turkish origin; "Iskender-Iulcarni (Alexander the Great), in the course of his conquests, demanded tribute from Katife, Queen of Smyrna. She refused insultingly and threatened to drown the king if he persisted. Enraged at her insolence, the conqueror determined to punish the queen by drowning her in a great flood. He employed Moslem and infidel workmen to make a strait of the Bosphorus, paying the infidel workmen one-fifth as much as the Moslems got. When the canal was nearly completed, he reversed the pay arrangements, giving the Moslems only one-fifth as much as the infidels. The Moslems quit in disgust and left the infidels to finish the canal. The Black Sea swept away the last dike and drowned the workmen. The flood spread over Queen Katife's country (drowning her) and several cities in Africa. The whole world would have been engulfed, but Iskender-Iulcarni was prevailed upon to open the Strait of Gibraltar, letting the Mediterranean escape into the ocean. (Gaster, pp.91-92)
Sumerian mythology: the gods were angry with humanity and destroyed the world with a flood, but the humans were warned of this and had built a ship with two individuals of each species aboard, because of this they survived the flood. (Gilgamesj-epic, tablet XI)
Hindu mythology: the god Vishnu changed himself into a huge fish and asked king Satyavrata to collect all species of plants and animals on earth, he then moved them away in a boat to protect them against a flood that covered the earth (Satapatha-brahmana I; VIII and Bhagavata-purana VIII; XXVI, 7)
Another myth from central India tells about a fish who warned a pious man about an upcoming flood, the man prepared a large box in which he, his sister, and a cock survived the flood.
Zoroastrian mythology: "After Ahura Mazda had warned Yima that destruction in the form of winter, frost, and floods, subsequent to the melting of the snow, are threatening the sinful world, he proceeds to instruct him to build a vara, 'fortress or estate,' in which specimens of small and large cattle, human beings, dogs, birds, red flaming fires, plants and foodstuffs will have to be deposited in pairs." (Avesta, videvdat, chapter 2)
Chaldean mythology: "There was a man by the name of Xisuthrus. The god Chronos warned Xisuthrus of a coming flood and told him to build a boat. The boat was to be 5 stadia by 2 stadia. In this boat Xisuthrus was to put his family, friends and two of each animal (male and female). The flood came. When the waters started to recede he let some birds loose. They came back and he noticed they had mud on their feet. He tried again with the same results. When he tried the third time the birds did not return. Assuming the water had dried up the people got out of the boat and offered sacrifices to the gods." (Smith, pp.42-43)
Germanic mythology: "The sons of Borr slew Ymir the giant; lo, where he fell there gushed forth so much blood out of his wounds that with it they drowned all the race of the Rime-Giants, save that one, whom giants call Bergelmir, escaped with his household; he went upon his ship, and his wife with him, and they were safe there. And from them are come the races of the Rime-Giants." (Prose Edda, Gylfaginning, p.19)
Celtic mythology: "Heaven and Earth were great giants, and Heaven lay upon the Earth so that their children were crowded in the darkness between them. One of their sons led his brothers in cutting up Heaven into many pieces. From his skull they made the firmament. His spilling blood caused a great flood which killed all humans except a single pair, who were saved in a ship made by a beneficent Titan. The waters settled in hollows to become the oceans." (Sproul, pp. 172-173)
The above myth shows similarities with the Greek myth about the skygod Ouranos and his wife the earthgoddess Gaia, in which their son Cronos unmans his father and takes over his role as supreme god.
Another Celtic myth from Wales says; "The lake of Llion burst, flooding all lands. Dwyfan and Dwyfach escaped in a mastless ship with pairs of every sort of living creature. They landed in Prydain (Britain) and repopulated the world." (Gaster, pp. 92-93)
Baltic mythology: a Lithuanian myth mentions that "From his heavenly window, the supreme god Pramzimas saw nothing but war and injustice among mankind. He sent two giants, Wandu and Wejas (water and wind), to destroy earth. After twenty days and nights, little was left. Pramzimas looked to see the progress. He happened to be eating nuts at the time, and he threw down the shells. One happened to land on the peak of the tallest mountain, where some people and animals had sought refuge. Everybody climbed in and survived the flood floating in the nutshell. God's wrath abated, he ordered the wind and water to abate. The people dispersed, except for one elderly couple who stayed where they landed. To comfort them, God sent the rainbow and advised them to jump over the bones of the earth nine times. They did so, and up sprang nine other couples, from which the nine Lithuanian tribes descended." (Gaster, p. 93)
Roman mythology: "Jupiter and Mercury, traveling incognito in Phrygia, begged for food and shelter, but found all doors closed to them until they received hospitality from Philemon and Baucis. The gods revealed their identity, led the couple
up the mountains, and showed them the whole valley flooded, destroying all homes but the couple's, which was transformed into a marble temple. Given a wish, the couple asked to be priest and priestess of the temple, and to die together. In their extreme old age, they changed into an oak and lime tree." (Ovidius, book 8)
Greek mythology: Zeus was angry about the proud humans and he decided to destroy them with a flood, but Prometheus (the creator of humans), warned his human son Deucalion and his wife Pyrrha, and placed them in a large wooden chest.
The flood came and destroyed the world, when the water level became lower the chest stranded on Mount Parnassus and Deucalion and Pyrrha re-populated the earth. (Apollodorus, bibliotheca I; VII, 2)
Another source tells that "An earlier flood was reported to have occurred in the time of Ogyges, founder and king of Thebes. The flood covered the whole world and was so devastating that the country remained without kings until the reign of Cecrops." (Gaster, p. 87)
Southwest Tanzanian mythology: the rivers began to flood and the god told two people to get into a ship and take seed and lots of animals with them, later the water retreated again and the earth was re-populated.
Chinese mythology: in China there are many local flood myths that all differ from eachother, the legends of the Miao people tell that "Thunder sent water and destroyed the earth", and that only a man named A-Zie and his sister survived on a boat.
Australian aboriginal mythology: the fury of the snake Yurlunggor caused a flood that covered the earth, after that he calmed down and the water retreated.
Incan mythology: the god Viracocha killed all humans with a flood except a man and a woman.
An alternative version tells that the gods caused a flood because they were angry about the humans being so evil, two brothers were warned of the flood by their llamas so they moved into a cave on a high mountain with their families and herds
Aztec mythology: a pious man named Tapi was warned by the gods of an upcoming flood, he built a boat and took his wife and pairs of all animals aboard, the flood came but they survived.
Kamchadalian mythology: the Kamchadale are a people in northeast Siberia who have the following myth; "A flood covered the whole land in the early days of the world. A few people saved themselves on rafts made from bound-together tree trunks. They carried their property and provisions and used stones tied to straps as anchors to prevent being swept out to sea. They were left stranded on mountains when the waters receded." (Gaster, p. 100)
As you can see mythological similarities are not limited to Indo-European mythologies alone, so the question whether or not a myth is of purely Indo-European origin is difficult to answer.
To give an example of this I shall now compare two non-related mythologies to eachother; Germanic mythology (Indo-European) and Korean mythology (non-Indo-European):
Germanic myths speak of a world tree named Yggdrasil, Korean myths also tell about a world tree.
Germanic myths tell about a god named Rigr (=Heimdall) who descends to earth to bring civilization, Korean myths tell about a god named Hwanung who descends to earth to bring civilization.
Germanic myths contain werewolves and so do Korean myths, in south-east Asia people even believe in both werewolves and weretigers.
Germanic myths speak of three gods (Odin, Vili, and Ve) who find two treetrunks on the beach and make humans out of them, other myths also tell about how the Germanic people consists of the Ingveones, Istveones, and Erminones, these groups originate from three gods.
Korean myths from the island of Cheju mention that three founding fathers (Yang, Ko, and Pu) found a chest on the beach that contained three princesses, from their union with these princesses the Korean people originates.
These similarities may be coincidence but can also have a common origin, who knows?
My assumption is that the similarities between the mythologies of so many people all over the world are caused by four reasons:
1. mutual influence by contact, which will especially be the case in the mythologies of people living close to eachother.
2. Indo-European origins, which may be the case with myths that only have parallels within the Indo-European language group.
3. Very old origins from a primeval human culture, which may sound a bit far-fetched at first but if all humans and languages can be traced back to the first groups of Homo Sapiens leaving Africa, then why can't certain mythological aspects originate from that period either?
4. universal way of thinking, all humans may be different but our brain functions in a similar way, we all have common desires, hopes, fears, and dreams, so it is very well possible that the same ideas originated from human minds in different places.
Here ends the story of the Indo-European migrations, a story that is hard to tell because so many pieces are missing, in this text I have given some basic information about the Indo-Europeans and focused on two Indo-European tribes where we know a bit more about than the rest to give you a better idea of their culture and identity, I have also listed some of the similarities between the various Indo-European religions and myths, even though it is almost impossible to say whether or not they are truly Indo-European or simply the result of mutual influences.
Despite the mysterious nature of the Indo-Europeans we are slowly learning more about them from archeological findings, which have already disproven the hypothesis that the Indo-Europeans took over control in northern Europe by physically conquering it because no traces of major battles have been found from that period, which suggests that in most places the Indo-European culture and language were adopted by the native people without a struggle.
Perhaps because of the power and political influence of the Indo-Europeans their identity became a universal identity that mixed with the native ways to create new cultures that were part indigenous and part Indo-European, much was lost and much was gained, but I don't think that the native culture of most peoples completely disappeared and traces of it can probably be found back under the Indo-European top layer, after all that's what makes every people unique.
The most famous Indo-European tribes are the Dorians (Greece and the Balkans), Hittites (the Middle East), Tocharians (western China), and the Aryans (India), because of the nazis there are many misconceptions about this last group so I shall tell a little bit more about them.
Another interesting Indo-European people are the Dorians, who invaded Greece around 1200BC and conquered the Bronze Age Mycenean cultures, they originally came from the north and quickly dominated most of mainland Greece, after that they crossed the Peloponnesian mountains and eventually reached the Greek islands, it is unknown why they were so successful but their superiour weapons (iron swords) probably played a role as well as their typically Indo-European warrior-culture.
Many of the similarities between the beliefs, gods, and myths of the Indo-European peoples may be of Proto-Indo-European origin but we must not forget that there are also many universal conceptions that humans everywhere around the world believe in, furthermore some of the myths may be based on real events that influenced many peoples around the world, for instance the Great Flood myths may have been caused by a real flood that was later exaggerated to mythic proportions, some people even believe that certain mythological similarities contain a universal truth that originates from the beginning of humanity when gods still walked the earth, but of course this is pure speculation.