Start with the thing that undoes the category: the sun is not the same kind of god twice. Put five solar deities side by side and they turn out to be doing three quite different jobs — making a journey, watching what happens, and holding an office — and no tradition emphasises all three equally. Which job a culture picks tells you more about the culture than about the sun.
Job one: the sun as traveller
The sun moves, it comes back, and something must be carrying it. What that something is depends entirely on how the people telling the story moved themselves.
Ra travels by boat, and there are two of them — a day barque and a night barque — because Egypt's transport was the river and the river ran both ways. The night crossing is the part that matters: the sun's passage under the world is a dangerous voyage through hostile country, culminating in a nightly fight with the serpent Apep, and the crew are gods with jobs. Egyptian funerary texts are largely maps and passwords for that route, because the dead travel it too.
Surya and Helios both drive. The chariot is the vehicle of a horse-culture, and the two traditions preserve details that are close enough to be interesting and different enough to keep the comparison honest: Surya's chariot has seven horses and a single wheel and is driven by a charioteer with no legs, while Helios's has four and he drives it himself. This is one of the places where a shared Indo-European inheritance is a genuinely serious proposal rather than a hopeful one, because the linguistic evidence supports it independently — the Bronze Age sun-disc-on-wheels from Trundholm in Denmark, drawn by a horse, sits in the same picture. It is also worth saying that a chariot is an obvious enough metaphor for a moving bright thing that convergence cannot be ruled out.
Utu rises through gates in the eastern mountain and sets through gates in the western one, and the cylinder seals show him doing it — sawblade in hand, rays from the shoulders, stepping up between two peaks. He is a commuter through architecture rather than a driver across sky.
Amaterasu does not travel at all. There is no Japanese chariot, no barque, no daily route. Her defining episode is a refusal to appear: she withdraws into a rock cave after her brother Susanoo's outrages, the world goes dark, and the assembled deities have to trick her out with a mirror, a rope and an obscene dance. That is a story about withdrawal and restoration, not about circuit. Anyone assembling a list of "sun gods and their chariots" has already misfiled the most politically important solar deity in East Asia.
Job two: the sun as witness
If you are looking for the strongest real cross-cultural pattern here, this is it, and it is far more robust than the chariot.
Nothing that happens in daylight happens unobserved, and a culture with that thought will hand the sun the job of remembering it. Utu is the god you swear by and the god who adjudicates; his Akkadian name Shamash appears at the top of the stele bearing Hammurabi's laws, handing over the rod and ring of office, and hymns address him as the one who lights the dark corners where wrongs are done. Surya is invoked in oaths and in courtroom-adjacent contexts and stands among the Navagraha as an observer of human fortune. Helios is the informant twice over in Greek myth: he tells Demeter who took her daughter, and he tells Hephaestus who is in bed with his wife. In the Homeric oath formulas he is called on alongside earth and sky precisely because he cannot be deceived.
The reason this pattern recurs is not diffusion. It is that the argument is short: a light source with total daytime coverage is the obvious candidate for the office of witness in any society that has to settle disputes without records. This is the class of parallel worth taking seriously — one where the shared cause is visible and does not require a migration to explain.
Egypt is the outlier again. Ra is a king, not a witness; the Egyptian office of moral accounting belongs to Maat and the weighing of the heart, and it is administered by Osiris and Thoth in the dark, not by the sun in daylight.
Job three: the sun as monarch
Where the sun is the head of the pantheon, politics has usually done the promoting.
Ra's supremacy is bound up with Heliopolis and then with the Fifth Dynasty's sun temples, and later with the fusion into Amun-Ra when Theban power made the merger convenient. Akhenaten's Aten is the extreme case: a single visible disc, no image, no mythology, and a court that moved to a new city to serve it — a reform so tied to one reign that it did not outlive him.
Amaterasu's supremacy is dynastic. The eighth-century chronicles that make her the ancestress of the imperial line were commissioned by that line. She is the head of the pantheon because a state said so, in writing, at a datable moment.
Compare that with Greece, where Helios is a Titan-descended figure of the second rank with one major cult — Rhodes, where the Colossus stood — and no seat on Olympus. A Greek could see the sun every day and still consider it religiously minor. Sovereignty in Greek myth belongs to a storm god, not a solar one, which is the reverse of the Egyptian arrangement and a useful check on the assumption that the biggest natural object gets the biggest god.
The claim to refuse: solar mythology
Every reader of nineteenth-century mythology eventually meets the idea that most myths are really about the sun. Friedrich Max Müller, a formidable Sanskritist, argued that mythology was a "disease of language" in which faded solar metaphors hardened into narrative — dawn became a maiden, the sun became a hero, and the hero's death was sunset. The method spread until practically every figure in every pantheon had been read as the sun by someone.
It collapsed, and the way it collapsed is instructive. Critics pointed out that the method could not be falsified — any story could be resolved into a sunrise with enough ingenuity — and Andrew Lang demonstrated the absurdity by applying the machinery to Müller himself and proving him a solar myth. Modern comparative work does not use it. But its residue is everywhere in popular writing: any golden-haired hero, any character who dies and returns, any figure with a wheel or a disc gets called "solar", and it means nothing. If a claim about a solar reading cannot point to an actual solar epithet, a solar cult site or a solar text, it is Müller's ghost.
The same caution applies to the Frazerian habit of treating every seasonal deity as a dying-and-rising sun. The gods who genuinely alternate — Dumuzid, Persephone — are not solar, and the solar gods do not die.
Gender, and why it matters here
English speakers absorb a male sun and a female moon from Greco-Roman convention and assume it is universal. It is not. Amaterasu is female and outranks her moon-brother Tsukuyomi. In Norse cosmology Sól is female and Máni male. In German the sun is grammatically feminine and the moon masculine, which is why translators of Norse material sometimes get it right by accident. Egyptian has both, with fierce solar goddesses — Sekhmet, Hathor as the Eye of Ra — operating alongside a male Ra. Any generalisation about "the sun as masculine principle" is a generalisation about one language family's grammar.
Three solar questions that keep coming back
Was Apollo the Greek sun god? Not originally, and the confusion is worth killing. Early Greek texts keep Apollo and Helios distinct — they appear in the same poems as different beings. The identification is a later development, encouraged by philosophical allegory and firmly established by the Roman period, at which point Sol Invictus, imperial iconography and eventually Renaissance painting fused them permanently. If you want the archaic Greek sun, it is Helios and he is comparatively unimportant.
Why does the sun need protecting at night? Because in Egypt the return of the sun was not assumed. The nightly defeat of Apep was thought of as an event that had to happen, and rituals existed to assist it — texts for the execration of the serpent were performed in temples. A cosmology where the sunrise is guaranteed produces no such literature; a cosmology where it is contested produces a great deal.
Is there a sun deity with no myths at all? Effectively, yes — the Aten, by design. Its theology deliberately stripped narrative out, leaving hymns about light and life-giving with no story to tell. It is the clearest demonstration available that a god's importance and a god's mythology are separable things.