The ancient Greeks from at least the fifth century BCE onward commonly believed that the worship of the god Dionysos originated in Asia and was introduced to the Greek world relatively late. For most of the twentieth century, scholars simply accepted this belief at face value and deemed the elements of Dionysos’s cult that they perceived as strange and exotic as definitive marks of his cult’s eastern origin. If you pick up any book about Greek religion that was published before around 1960, it will almost certainly claim that Dionysos was a late addition to the Greek pantheon. Even today, people online still commonly repeat this claim as though it were fact.
For at least the past thirty years, though, scholars of ancient Greek religion have known for certain that Dionysos was not, in fact, a late entry to the Greek pantheon from the east at all. Instead, extremely ancient clay tablets written in a very early form of Greek definitively attest that the Greeks were already worshipping Dionysos as early as the fourteenth century BCE—a thousand years before Plato was even born. In light of this fact, the fact that the ancient Greeks believed that Dionysos was a recent addition to their pantheon takes on new meaning and potentially reveals much about how the Greeks thought about foreignness.
Dionysos’s true origin
Sometime around 1600 BCE or thereabouts, a civilization emerged in mainland Greece. The people of this civilization were early Greeks who spoke a very archaic form of the Greek language. Modern scholars have dubbed these early Greeks “Mycenaeans” after Mycenae, which was the largest and most impressive citadel in mainland Greece during this period.
At this time, another civilization was already flourishing on Krete, the southernmost of all the Greek islands. Modern scholars have dubbed this civilization “Minoan,” after King Minos, who supposedly ruled the island according to much later Greek myth. The Minoans had developed and were using a writing system, which modern scholars have named Linear A.
Sometime around 1400 BCE or thereabouts, the Mycenaeans developed their own syllabary writing system based on Linear A, which modern scholars have named Linear B. They began using this script to write administrative records in their own language, Mycenaean Greek. A substantial corpus of clay tablets that bear writing in Mycenaean Greek using the Linear B script have survived to the present day and scholars are able to read them.
All the surviving documents in Linear B are administrative records; they include no works of literature or philosophy. Nonetheless, they reveal a great deal of valuable information about Mycenaean daily life. Perhaps most excitingly, they reveal that the Mycenaeans of the Late Bronze Age were already worshipping many of the deities that their descendants worshipped centuries later in the classical period, including Zeus, Poseidon, Hera, Athena, Hermes, and Artemis (Chadwick, The Mycenaean World, 84–101; Burkert, Greek Religion, 43–46).
ABOVE: Photograph from Wikimedia Commons of a clay tablet with writing on it in Linear B, recovered from the archive of the Mycenaean city of Pylos
The tablets also reveal that the Mycenaean Greeks were already worshipping Dionysos in the Late Bronze Age. Three different tablets found at two different sites directly attest Dionysos as the name of a deity in the form “di-wo-nu-so.” The oldest of these is PY Xa 1419, a tiny, fragmentary tablet that was discovered at the Mycenaean citadel of Pylos in the Peloponnesos in mainland Greece and dates to the fourteenth century BCE.
The reverse side of this same tablet bears the word “wo-no-wa-ti-si,” which seems to be a Linear B rendering of ϝοινοϝάτισσι (woinowátissi), a dative plural form of a feminine noun that probably refers to women from a place called Ϝοινόϝᾱ (Woinówa), a name which derives from the Mycenaean Greek word ϝοῖνος (woînos), meaning “wine.” This possibly suggests that Dionysos may have already been associated with female followers and wine in the fourteenth century BCE (Bernabé, “Dionysos in the Mycenaean World,” 28–29).
The second oldest surviving Linear B tablet that mentions Dionysos is Gq 5, which was discovered at the site of Chania on the western part of the northern coast of Krete. This tablet reads (in Alberto Bernabé’s translation from “Dionysos in Mycenaean World,” 25): “To the sanctuary of Zeus. To Zeus, one amphora of honey. To Dionysos two [amphorae of] honey.” The fact that this tablet lists Zeus and Dionysos as receiving offerings together strongly suggests that the Mycenaeans already regarded Dionysos as the son of Zeus, even in the thirteenth century BCE (Bernabé, “Dionysos in the Mycenaean World,” 25–26).
A second tablet discovered at Pylos, PY Ea 102+107, which dates to sometime around 1200 BCE or thereabouts, also mentions Dionysos. It reads (as Bernabé renders it): “To the sacrificial hearth of Dionysos two large parts and two small parts of grain” (“Dionysos in the Mycenaean World,” 27).
Together, these three tablets indisputably attest that the Mycenaean Greeks were already worshipping Dionysos under his familiar name in the fourteenth and thirteenth centuries BCE.
ABOVE: Photographs (left) and hand copies (right) of the recto (upper) and verso (lower) sides of PY Xa 1419, a Linear B tablet discovered at Pylos dating to the fourteenth century BCE that bears the oldest surviving occurrence of the name Dionysos (Palaima, “Evidence for the Influence of the Knossian Graphic Tradition at Pylos,” Plate I)
The classical Greek perception of Dionysos as a recently imported god from the east
Paradoxically, despite the fact that, by the fifth century BCE, Dionysos had a long history of worship in Greece stretching back almost a millennium or more, the ancient Greeks from at least that century onward generally thought of him as having originated somewhere outside of Greece and entered their own pantheon quite late.
The Greek historian Herodotos of Halikarnassos (lived c. 484 – c. 425 BCE) in his Histories 2.144 expressly identifies the Egyptian god Osiris as Dionysos. Two chapters later (in Hist. 2.146.2), he speculates that the Greeks first learned about the gods Dionysos and Pan from the Egyptians at a later time than when they learned about the other deities and that this is the reason why the Greeks regarded these two gods as younger than the others. He writes, in Greek:
“δῆλά μοι γέγονε ὅτι ὕστερον ἐπύθοντο οἱ Ἕλληνες τούτων τὰ οὐνόματα ἢ τὰ τῶν ἄλλων θεῶν: ἀπ᾽ οὗ δὲ ἐπύθοντο χρόνου, ἀπὸ τούτου γενεηλογέουσι αὐτῶν τὴν γένεσιν.”
This means, in my own translation:
“It is clear to me that the Hellenes [i.e., Greeks] learned the names of these [gods] later than those of the other deities. And, from the time when they learned, they assigned their birth.”
ABOVE: Photograph from Wikimedia Commons of a Roman marble bust of the Greek historian Herodotos, based on an earlier Greek original
In a similar vein, the Athenian tragic playwright Euripides (lived c. 480 – c. 406 BCE) portrays Dionysos as having arrived in Greece from the east in his tragedy The Bacchae, which was first performed at the City Dionysia in Athens in spring 405 BCE. At the very beginning of the play, Dionysos himself appears on stage and delivers a long monologue in which he describes his own journey from the lands of Asia to Greece, in lines 13–25:
“λιπὼν δὲ Λυδῶν τοὺς πολυχρύσους γύας
Φρυγῶν τε, Περσῶν θ᾽ ἡλιοβλήτους πλάκας
Βάκτριά τε τείχη τήν τε δύσχιμον χθόνα
Μήδων ἐπελθὼν Ἀραβίαν τ᾽ εὐδαίμονα
Ἀσίαν τε πᾶσαν, ἣ παρ᾽ ἁλμυρὰν ἅλα
κεῖται μιγάσιν Ἕλλησι βαρβάροις θ᾽ ὁμοῦ
πλήρεις ἔχουσα καλλιπυργώτους πόλεις,
ἐς τήνδε πρῶτον ἦλθον Ἑλλήνων πόλιν,
τἀκεῖ χορεύσας καὶ καταστήσας ἐμὰς
τελετάς, ἵν᾽ εἴην ἐμφανὴς δαίμων βροτοῖς.
πρώτας δὲ Θήβας τῆσδε γῆς Ἑλληνίδος
ἀνωλόλυξα, νεβρίδ᾽ ἐξάψας χροὸς
θύρσον τε δοὺς ἐς χεῖρα, κίσσινον βέλος:”
This means, in my own translation:
“And I have left behind the much-gold-having lands of the Lydians
and Phrygians, and the sun-scorched plains of the Persians,
the Baktrian walls and the bad-wintered land
of the Medes, prosperous Arabia,
and all Asia, which, along the salty sea,
lies, with Hellenes and barbarians mingled of the same,
having many beautiful-towered cities.
There, I danced in circles and laid down my
rites, so that my divinity be displayed to mortals.
And, for the first time, toward Thebes of this land Hellas
I let out a loud ululation, fastening the fawnskin,
giving the thyrsos to the hand, an ivy-covered staff.”
ABOVE: Photograph from Wikimedia Commons of a Roman marble bust on display in the Museo Pio-Clementino in the Vatican Museums, intended to represent the ancient Athenian tragic playwright Euripides, based on an earlier Greek bust dating to the fourth century BCE
Traditions from the Hellenistic Period (lasted c. 323 – c. 30 BCE) and later frequently claim that Dionysos originated even further east—in India. For instance, the Greek historian Diodoros Sikeliotes (lived c. 90 – c. 30 BCE) claims in his Library of History 3.63.3–5 that there was more than one Dionysos and the first of them was Indian. He writes, as translated by C. H. Oldfather for the Loeb Classical Library, with some edits of my own:
“The most ancient Dionysos was an Indian, and since his country, because of the excellent climate, produced the vine in abundance without cultivation, he was the first to press out the clusters of grapes and to devise the use of wine as a natural product, likewise to give the proper care to the figs and other fruits which grow upon trees, and, speaking generally, to devise whatever pertains to the harvesting and storing of these fruits.”
“The same Dionysos is, furthermore, said to have worn a long beard, the reason for the report being that it is the custom among the Indians to give great care, until their death, to the raising of a beard. Now this Dionysos visited with an army all the inhabited world and gave instruction both as to the culture of the vine and the crushing of the clusters in the wine-vats (lenoi), which is the reason why the god was named Lenaios. Likewise, he allowed all people to share in his other discoveries, and when he passed from among men he received immortal honor at the hands of those who had received his benefactions.”
“Furthermore, there are pointed out among the Indians even to this day the place where it came to pass that the god was born, as well as cities which bear his name in the language of the natives; and many other notable testimonials to his birth among the Indians still survive, but it would be a long task to write of them.”
ABOVE: Mosaic from the House of Dionysos on the Greek island of Delos, dating to the late second century BCE, depicting Dionysos riding on the back of a panther, currently held in the Archaeological Museum of Delos
The decipherment of Linear B
In the nineteenth and early twentieth centuries, the vast majority of scholars of Greek mythology, literature, and religion regarded ancient Greek authors’ portrayal of Dionysos as a late foreign addition to their pantheon as essentially accurate. One of the most noted proponents of this view was the German classical philologist Erwin Rohde (lived 1845 – 1898).
This situation drastically changed as a result of the decipherment of Linear B in the 1950s, which was one of the single most important breakthroughs in the study of the ancient world in the entire twentieth century and one which had an immense, wide-ranging impact on scholarly understanding of Greek history.
The American scholar Alice Kober, a brilliant female professor of the classics at Brooklyn College, laid the scholarly groundwork for Linear B’s decipherment. She began studying the script in the early 1930s and spent nearly two decades working tirelessly to decipher it. She published a series of three groundbreaking papers in 1945, 1946, and 1948, which demonstrated that Linear B was an inflected language and brought the script much closer to decipherment. Tragically, despite the fact that she devoted most of her scholarly career to trying to crack Linear B, she didn’t live to see it actually deciphered; she died on 16 May 1950 of an unrecorded illness at the age of only forty-three.
Just two years after Kober’s death, news of Linear B’s decipherment came from quite an unexpected source. On 1 July 1952, a young English architect and amateur cryptographer named Michael Ventris announced on a BBC radio broadcast that, relying heavily on Kober’s earlier work, he had found preliminary success in deciphering the script as a syllabary used to write a very early form of Greek.
John Chadwick, an English philologist who was a lecturer of classics at the University of Cambridge at the time, heard the broadcast and quickly contacted Ventris. The two men began working together in close collaboration and, the following year, they coauthored a paper together in The Journal of Hellenic Studies, a respected academic journal, in which they formally outlined their proposed decipherment in detail for a scholarly audience for the first time (Ventris and Chadwick, “Evidence for Greek Dialect in the Mycenaean Archives”).
Three years later, in 1956, Ventris and Chadwick published a book: Documents in Mycenaean Greek, which presented interpretations and translations of Linear B tablets. Tragically, like Kober before him, Ventris met an untimely demise; he died on 6 September of the same year the book was published in a car accident at the age of only thirty-four. Nonetheless, Chadwick carried on Ventris’s legacy by continuing the work he had started with him over the following decades.
Unfortunately, even though Ventris himself always acknowledged that his breakthrough relied on Alice Kober’s years of intensive research before him, most popular accounts of the decipherment of Linear B make no mention at all or only brief mention of Kober’s work and incorrectly portray Ventris as a brilliant amateur who deciphered Linear B all on his own. In this way, Kober is something of the Rosalind Franklin of Aegean prehistory.
ABOVE: Alice Kober (left), Michael Ventris (center), and John Chadwick (right), the three researchers who played the greatest role in deciphering Linear B
A seismic shift in scholarly understanding of Dionysos
In any case, one of the tablets that Ventris and Chadwick translated and published in their book in 1956 was PY Xa 102, a piece of what is now known as PY Ea 102+107 on which Dionysos’s name was clearly legible (Ventris and Chadwick, Documents in Mycenaean Greek, 127). Four years later, in 1960, excavators unearthed PY Xa 1419 at Pylos. Chadwick included it in the second edition of Documents in Mycenaean Greek, which he published in 1973.
In both of these cases, all that was really attested was the name Dionysos; scholars did not have enough context to know for certain that these tablets used it specifically as the name of a god. Then, in 1990, excavators uncovered Gq 5 at Chania. This discovery provided the first clear, undisputed case of Dionysos being used as a divine name in Linear B (Bernabé, “Dionysos in the Mycenaean World,” 24).
Two years later, the scholar E. L. Bennett identified the two different pieces of PY Ea 102+107 as belonging to the same tablet, a reunification which brought enough context to show that that tablet definitely uses Dionysos as a divine name as well (Bernabé, “Dionysos in the Mycenaean World,” 24).
Thus, scholars have known that the name Dionysos appears in Linear B tablets from the Late Bronze Age for well over half a century now and have known with great confidence that it occurs specifically as a divine name for over three decades at least.
ABOVE: Front cover of the original 1956 edition of the book Documents in Mycenaean Greek by Michael Ventris and John Chadwick
Why the ancient Greeks perceived Dionysos as foreign even though he wasn’t
We know that speakers of the Greek language were already worshipping Dionysos in Greece at least 3,300 years ago. The only question that remains is why the later ancient Greeks came to regard him (incorrectly) as a late, foreign addition to their pantheon. Scholars don’t all necessarily agree on the answer to this question and this topic is fertile ground for future inquiry, but I would argue that a few factors most likely played a role.
The first factor is that the Greeks of the Classical Period onward most likely didn’t have access to accurate information about Dionysos’s long history of worship in Greece. They most likely knew less about Linear B than western scholars in the twentieth century did before Alice Kober’s work toward deciphering it. Meanwhile, writing in the Greek alphabet—the only writing that they could understand—only went as far back as the late ninth century BCE at the earliest.
In the absence of this information, the Greek authors whose works have survived to the present day (who, we should recall, were almost exclusively men from at least moderately well-off families) may have perceived Dionysos as being of recent foreign origin because they saw the ecstatic and excessive aspects of his worship as inconsistent with their own conception of Hellenicity (that is, Greekness). They may have therefore sought to distance the cult from Hellenicity by portraying it as being of recent foreign importation.
In addition to these factors I have outlined, the scholar Eric Csapo argues that the Greek perception of Dionysos as foreign is also connected to his liminality, which means his quality of existing in between recognizable states without being in one state or the other. Csapo points out that, in Euripides’s Bacchae, Dionysos describes himself as having been born in Thebes, but yet he has spent all his time until the start of the play in Asia and he comes to his own birthplace as a foreigner. Thus, in Thebes, he is simultaneously both native and foreign (Csapo, “Riding the Phallus for Dionysus,” 255).
Whatever one makes of all this, the name of the Loud-Roaring One echoes to the present through at least thirty-three centuries of history.
ABOVE: Photograph from Wikimedia Commons of a Roman marble head of Dionysos dating to the second century CE, depicting him as an androgynous youth
Works cited
- Bernabé, Alberto. “Dionysos in the Mycenaean World.” In Redefining Dionysos, edited by Alberto Bernabé, Miguel Herrero de Jáuregui, Ana Isabel Jiménez San Cristóbal, and Raquel Martín Hernández, 23–37. Berlin: De Gruyter, 2013.
- Burkert, Walter. Greek Religion, translated by John Raffan. Cambridge: Harvard University Press, 1985.
- Chadwick, John. The Mycenaean World. Cambridge, England: Cambridge University Press, 1976.
- Csapo, Eric. “Riding the Phallus for Dionysus: Iconology, Ritual, and Gender-Role De/Construction.” Phoenix 51, no. 3/4 (1997): 253–95. https://doi.org/10.2307/1192539.
- Palaima, Thomas. “Evidence for the Influence of the Knossian Graphic Traditon at Pylos.” Concilium Eirene XVI 3 (1983): 80–84.
- Ventris, Michael, and John Chadwick. Documents in Mycenaean Greek. Cambridge: Cambridge University Press, 1956.
- — “Evidence for Greek Dialect in the Mycenaean Archives.” The Journal of Hellenic Studies 73 (1953): 84–103. https://doi.org/10.2307/628239.
Interesting article. Will read it later, might get my mind off today which has been very painful.
I’m truly sorry to hear that! I hope that you are doing better now than you were when you wrote this.
Do we have any knowledge of the Mycenaean Greeks’ mythology?
Scholars currently know nothing reliable about the Mycenaeans’ mythology aside from the names of some of their deities and some basic inferences about who these deities were based on what we know the Greeks in later periods that are better historically documented believed about them. There are no surviving texts in Linear B that retell any kind of myths; all we have are administrative documents, some of which mention certain deities’ names, usually in the context of recording people making offerings to them.
Thanks for this fascinating article, and for telling us about Alice Kober, who I had never heard of before. The analogy to Rosalind Franklin occurred to me too.
Yes, it is a real tragedy that she has received so little credit for her work.
Lovely article, as always!
I am disappointed to say I studied the Bronze Age Aegean some months ago and Alice Kober was never mentioned, only Ventris.
Did not the decipherment of Linear B also disprove the idea that the Mycenaeans had been a “Pelasgian” or pre-Greek people as scholars had assumed before? I think I have read of that at least.
And do you think, when ancient historians describe for example Dionysus as a historical conqueror in Asia or Hephaestus as an early king in Egypt, that they are engaging in euhemerism or that they do view these gods as having been on Earth in the distant past but that they are still divine?
Thank you so much! I’m glad to hear that you enjoyed the post!
The decipherment of Linear B has proven that the Mycenaeans spoke a form of the Greek language and worshipped many of the same deities that the Greeks worshipped in later periods that are better historically attested. Surviving documents in Hittite also refer to the Mycenaeans by the name Aḫḫiyawā, which appears to be a Hitte rendering of Ἀχαιϝοί (Achaiwoí), which is the older form of Ἀχαιοί (Achaioí), which is one of several names that the Homeric epics use for the Greeks. This evidence suggests that the Mycenaeans most likely called themselves “Ἀχαιϝοί.” All this evidence strongly indicates that there was continuity of ethnic and cultural identity between the Mycenaeans of the Bronze Age and the Greeks of later periods who are better historically attested.
To answer your second question, the ancient Greeks and Romans believed that exceptional human beings could become deities. Thus, for ancient authors, believing that deities once existed as human beings on earth wasn’t necessarily incompatible with believing that they still exist as real supernatural beings. Diodoros Sikeliotes in particular seems to have held both views simultaneously.
Thank you! I did actually not remember that the Mycenaeans called themselves Achaeans too. And glad to get some clarification on euhemerism and apotheosis, a quite complicated topic!
You’re welcome! I’m glad to hear that you found my reply helpful!
Hi Spencer,
another excellent post…!
Could you please clarify a point ?
The fact that classical age Greeks perceive Dionysus as a late comer from abroad does not provide clues as to ‘when’ the young god came form abroad, he is just a later arrival compared to Zeus and the other gods.
We do know that Greeks through the centuries, and up to Christianity, had their mythology which to them was more of a real “history” and not just fairy tales and, even though we do not have the written continuity between texts in Linear B and the later Greek alphabet, we can quite safely assume that the narrated myths continued as usual and Herodotus et al. just went on writing accordingly. after all the Homeric epics narrate events from five centuries earlier.
So I believe that the later, classic texts are simply repeating the centuries old myths but now actually written on “paper”…
Thanks for your comments.
Yes, it is still possible that Dionysos was introduced to Greece from abroad, but, if that is the case, he must have been introduced to the Greek world very early, since, with the evidence from Linear B, he is now actually one of the earliest directly attested deities in Greece.
For reference, Aphrodite and Hades are not currently attested anywhere in Linear B at all.
I saw an interview with Jim Morrison of The Doors where he referred to someone’s idea that he was an avatar of Dionysos.
Worked for me
Thank you very much for the article! I have a translation of Chadwick’s book at home, but I haven’t started reading it yet. By the way, I also have several books with ancient Greek and Hittite texts translated and commented by Bernabé (including one about the Orphic fragments, which I mentioned before in other comment), but sadly no one of them about this subject.
Chadwick’s book (The Mycenaean World) is quite good, although it is also quite dated now, since scholars have discovered a lot more about the Mycenaeans in the decades since he published it. I cited it here mainly because it is important for the historiography of Mycenaean religion, since it was one of the first books to examine the subject using the Linear B texts that were then newly-deciphered.
Big enterprises such as the understanding of an unknown script are never developed by a single person. Ventris was the genius who made the final step, but he was “standing on the shoulders of giants” (especially Kober). The same can be said of Champollion, for example, or Andrew Wiles, who became one of the big names in contemporary history of mathematics when he gave a proof of Fermat’s famous Last Theorem, thirty years ago, after studying for several years the groundbreaking work of Taniyama, Shimura, Frey, and others. Many accounts intended for a wide public tend to oversimplification.
Hi Spencer what a great informative article. Never know this about the late greeks denying one of their deities (Dionysus) to the point of considering it foreign and not native to them.
Would they (the Greeks) have wanted to place him in a secondary role like Ares?
What I’m trying to say is that, like him (Ares), the lord of violence and senseless war, seen as negative characteristics not to imitate, Dionisios represented the pleasant excess, in this case, of wine and its negative effects on its consumption. .
Do not deny his existence, but if possible give him as little worship as possible, like Ares.
Well, no more to say, except. Good luck in your works.
Actually, the ancient Greeks throughout their recorded history worshipped Dionysos prolifically and held him in quite high honor. Unlike Ares, he was a hugely important deity in their religion. The Athenians, for instance, honored him with no less than four major festivals each year: the Rural Dionysia (which took place in the month of Poseideon, roughly corresponding to late December to early January on the Roman calendar), the Lenaia (which took place in Gamelion, roughly corresponding to our late January to early February), the Anthesteria (which took place in Anthesterion, roughly corresponding to our late February to early March), and the City Dionysia (which took place in Elaphebolion, roughly corresponding to our late March or early April). In addition to being an important god in Greek public religion, there was also a major mystery cult associated with him.
This is part of what makes Greek writers’ portrayal of Dionysos as foreign so puzzling; he was a hugely important deity in Greek religion who was worshipped in Greece from a very early date and yet Greek authors still portrayed his cult as being of foreign importation.
Spencer, I noticed that you deleted this article:
https://talesoftimesforgotten.com/2019/03/02/pagan-survivals-fact-and-fiction/ It’s a few years old, so it probably wasn’t as good as your more recent articles, and I get that. Is there any more specific reason for this one?
Wow, I’m surprised that you noticed that I deleted that post so quickly, since I just deleted it yesterday.
I partly explain my reasons for deleting it in this thread on Twitter. The short version is that the post contained a large number of claims that I now feel were egregiously unsupported by evidence and it was also unwarrantedly dismissive of contemporary paganism.
(My comment below should have gone here)
Well, to be fair, I think contemporary paganism (at least the Nordic type) deserves some contempt. I know a historian who says that Ásatrúar are “Christians of Thor,” meaning that they have a structured religion and a concept of faith which are ironically inherited from Christianity, not from old paganism.
Spencer, what do you think about the hypothesis proposed in the Channel Overly Sarcastic Production about the subject, in which the OP proposes that maybe it was because of some social aspects related to the nature of the cult?
https://youtu.be/5brAr51ip_k?t=330
I look at your old articles all the time. And what was wrong with your definition of continuity?
The cult of Dionysus was heavily restricted in Rome where it was actually foreign, so its possible the surviving Greek sources were curated to support the Roman perspective. Diodorus was born in Sicily well after the Roman conquest.
Herodotus thinks all gods are Egyptian in origin. His argument for Dionysus being younger is explained pretty well in his actual argument. Sons have to be younger than fathers.
The idea of foreign invaders who aren’t really foreign also appears in the Heraclid genealogy. Exiles fighting to return was also a common reality.
As a traveling culture hero Dionysus has a lot of overlap with less divine personages such as Pythagoras who was also seen as transmitting Indian wisdom. I would suspect that this is influenced by Cynic derived cosmopolitanism.
A lot of Hellenistic sources are written by Greek colonists who want proof that their religious traditions have a divinely ordained place in their new land. There’s also a conflict between localised cults like the Eleusinian mysteries that can’t expand and are only accessible to those who can afford a pilgrimage and more mobile or franchisable cults. The supposed Egyptian origin of the Eleusinian mysteries is probably Ptolomaic propaganda used to justify the importing of Eleusinian elements into the cult of Isis, which it turn could justify expanding the more Eleusinian than authentically Egyptian Mysteries of Isis outside of Egypt as a tool of Ptolomaic soft power.
Modeling an ancient Dionysus as a Hellenistic conqueror both helps legitimate Hellenistic Kings spreading Greek cults as political tools while allowing the worshippers of those cults to keep their euhemerised Dionysus as older and therefore superior to the dubiously legitimate actions of more resent rulers.
By making Greek deities less Greek they become better suited for Greek cultural imperialism. This in turn is very convenient for the Romans who have much more reason to be embarrased by a Greek centric view of cultural influence than a more cosmopolitan one. If the Greeks are just copying Indians and Egyptians Roman cultural dependence on Greece is less of an issue.