The idea to investigate the subject of this article came to me the other day while re-reading a passage from the astrological treatise Tetrabiblos in which, referring to the characteristics of the inhabitants of different climates, Claudius Ptolemy, the great astronomer of Antiquity, stated that:
the southernmost of them [i.e., of the inhabitants of the region between the summer tropic and the arctic circle] are […] better versed in the knowledge of things divine because their zenith is close to the zodiac and the planets revolving about it. 
This passage made me think more deeply about the connection between the position of the Sun in the sky and the emergence of certain religious ideas, especially those of a monistic/monotheistic nature. I rushed to the atlas to check more thoroughly the places through which the Tropic of Cancer passes.
The Tropic of Cancer is parallel to the Equator at an angle of 23°26′ north of the Equator. What is happening at this latitude?
Well, due to the tilt of the Earth’s axis, the Ecliptic – the circle that marks the apparent path of the Sun – is also at an angle of 23°26′ to the equatorial plane. When the Sun enters the sign of Cancer an observer in a locality located on the Tropic of Cancer, at midday, sees the Sun exactly above his head (at the zenith, at an angle of 90 degrees to the horizon), at its maximum declination, that is, at its maximum elevation above the Equator. Even if, throughout the year, the Sun reaches its zenith (twice a year) in all localities between the two tropics, at the Tropic of Cancer it does so right at the summer solstice when the length of the day (therefore the presence of light) is the greatest (in the Northern Hemisphere). On this day, at noon, the objects cast no shadow.
Well, after the analysis I noticed that on a very narrow strip (of only a few degrees) along the Tropic of Cancer are strung the places of origin of all monotheistic religions, but also of other religions with a monistic character.
Throughout history, Egypt maintained a polytheistic cult, but it was also Egypt that, for a short period, gave the world its first attempt at monotheism. Akhenaton / Akhenaten (Amenhotep the 4th) – pharaoh of Ancient Egypt (and husband to the famous Nefertiti) who lived in the 14th century CE – was probably the first founder of a monotheistic religion. He abolished the polytheistic cult by declaring that Aten (a solar deity assimilated to Ra – the supreme god of sunlight) was the supreme god (God) and forbidding the worship of other gods and idols (in fact the cult of ‘Atenism’ was monotheistic in theory, but henotheistic in practice). Akhenaten thus tried to replace the polytheistic cult of Egypt with the cult of Aten, the god of the Solar Disc.
Why was Ra, the God of the Sunlight, the supreme deity of the Egyptian polytheistic cult and why did the Aton, the God of the Solar Disk, become the supreme deity of Akhenaten’s monotheism? I think that this is symbolically correlated with the fact that Luxor is very close to the Tropic of Cancer, where – at the time of its maximum elevation in declination (at the summer solstice) the Sun is at the observer’s zenith, i.e., above the head of the observer!
Ra, the deity associated with sunlight, initially established itself as the supreme deity of the Egyptian pantheon; later, the divinity symbolically associated with the sun disk itself was imposed (for a time) as the sole god.
Even though Akhenaten built another city dedicated to Aten (Amarna – located at 27° 38′, almost 4° from the Tropic), very likely his monotheistic ‘revelation’ (and ‘revolution’) crystallized at Karnak / Luxor ( 25° 41′N – only 2° from the Tropic).
The sun near the zenith of Mount Sinai. The Monotheism of Moses
Compared to the monotheistic cult initiated by Akhenaton, the first signs of monotheistic rhetoric within the Yahwist cult appear much later (after the period of the Assyrian conquest, during the reign of Josiah and the Babylonian exile), and the actual establishment of a monotheistic cult appeared even later, during the period of Persian or Seleucid rule.
But is it a coincidence that Moses – the alleged founder of Yahwism was placed in the same century as Akhenaten (according to one of the traditional chronologies)? Is it a coincidence that, in the biblical legend, Moses is raised in the court of Pharaoh and bears an Egyptian name like his brother Aaron? And is it a coincidence that part of the fantastic (hi)story told by the Israelite Bible (beginning with the adventures of Jacob and continuing with the legend of Moses) is set in ancient Egypt? Is it a coincidence that the affirmation of the worship of YHWH (Yahweh) and the beginning of Jewish monotheism occur during the exodus from Egypt?
Renowned Egyptologists – such as Jan Assmann  – state that the transmission or ‘translation’ of the idea of monotheism from the Egyptians to the Israelites is very plausible.
As early as the beginning of the last century, Sigmund Freud speculated that Moses was probably a priest of the Aten cult who was forced out of Egypt after the death of Akhenaten along with his followers. Freud (in unison with the Egyptologist Arthur Weigall who wrote a popular biography of Akhenaten) also considered that the appellation ‘Adonai’ correlated with YHWH also comes from Aten (although this hypothesis was not supported by other researchers).
Archaeologically and historically, it is known that the Israelites did not arrive from Egypt, but were indigenous inhabitants of the Land of Canaan who fought with other tribes for local supremacy. The legend of the escape from Egypt could, however, have its origin in the story of a very small group of Israelites who managed to escape from Egyptian slavery and brought with them very innovative religious ideas to the Land of Canaan. We do not know for sure, but one of these unusual ideas may have been that of the exclusive worship of one god. This idea originated in the worship of the Canaanite god Yahweh, gradually developing into an increasingly strong belief that adopting Yahweh as the sole national god would bring dominion over the Land of Canaan. The Israelites’ ‘covenant’ with this god was meant to be as ‘pecuniary’ in its effects as they were to receive the ‘Land of Promise’ (Land of Canaan) and the status of ‘Chosen People’ in exchange for his exclusive worship according to the heno- or monotheistic model once established by Akhenaton.
Moreover, it is amazing how much the Hymn to Aten:
[O God of the Sun] besides You there is none!
resembles Shema Israel, the prayer that expresses the very essence of Judaism (Psalm 104):
Hear, O Israel: the Lord (YHWH) is our God, the Lord (YHWH) is one!
Although Yahweh / YHWH – the god of the Israelites – was not a solar deity, a solar-type monotheistic rhetoric may have been amalgamated with the attributes traditionally associated with him. The solar language used about Yahweh in several biblical passages is telling in this sense .
The latitude of Mount Sinai (associated with the biblical place where Yahweh would have revealed His Law to Moses) is 28° 32′N, which is 5° from the Tropic of Cancer.
The Sun and the Christian Monotheism
It is debatable whether Christianity is a monotheism. It can be argued that the introduction of other divine persons – Christ and the Holy Spirit / Spirit – on the same level as God the Father expresses a disguised polytheism (through the paradoxical creed in the Trinity which would sound something like this: ‘God the Father is God, Christ is God, the Holy Spirit is God, but God the Father is not one with Christ, who is not one with the Holy Spirit, who is not one with God the Father, but also through the worship of a ‘Mother of God’ – somewhat similar to that of the goddess Isis – and by worshipping ‘graven figures’ – icons and other representations).
Without speculating upon the idea of a theological borrowing, it must be said, however, that the biblical story of Jesus reflects very well the Egyptian mythology associated with the solar god and the myth of the death and resurrection of Osiris (symbolized by the apparent ‘death’ and ‘resurrection’ of the Sun in the zodiacal cycle). Like Akhenaten who declared himself the only and eternal ‘son’ of his only God, Jesus was also declared the only son of God by his followers. The birth of Jesus is celebrated on the same day as the Roman holiday Sol Invictus (Birth of the Invincible Sun), on December 25.
Jerusalem (at approx. 8° N of the Tropic) was a key focus for the cult of Jesus, even if the doctrine by which Jesus was elevated to the rank of the Only Begotten Son of God (and was identified with Him) was – probably – elaborated elsewhere, long after his death.
The sun at its zenith in Mecca and the birth of Islamic monotheism
Muhammad received his revelation that ‘God is One’ near Mecca, a locality located at 21° 25′N, i.e., only 2° south of the Tropic of Cancer. The other important place of Muhammad’s activity was Medina (situated less than 1° from the Tropic).
Until then, the Arabs had been worshipers of polytheistic cults. Did the light of the ‘Sun of Monotheism’ also hit Muhammad directly on the top of his head – right in the cave where he was praying? Probably…
The Sun and the Religion of The One: Neoplatonism
Plotinus, the founder of Neoplatonism was born in Lower Egypt and studied for 11 years in Alexandria, Egypt (31° 12′ N, i.e., 7° 40′ N of the Tropic) where in the middle of the 3rd century A.D. he began to lay the foundations of his Neo-Platonic system. Neoplatonism conceives a supreme principle that does not contain any distinction or multiplicity, called ‘The One’ (or the Source, the Monad), conceived as Supreme Light. From this supreme principle emanates the Divine Intellect (Nous) which Plotinus likened to the ‘Sun’. The analogy with the solar principle is most obvious here.
The Tropic of Cancer in India and the unity of Brahman
Although we don’t know exactly where Brahmanism originated, it seems that it developed in the region called Āryāvarta – an area crossed by the Tropic of Cancer where the cult of solar deities from the Hindu pantheon (such as Āditya / Sūrya) also developed.
Brahman – the Supreme Spirit, the Eternal Absolute, i.e., the Godhead conceptualized by the Vedic and Upanishadic tradition – and the corresponding personal principle, Ātman (the Individual Self) have their attributes as closely mirrored by those which the Sun symbolizes: eternity, radiance, consciousness, unity, truth. Just as the light of the Sun radiates and touches the earthly things, so the Light of Brahman pervades all that exists.
In asserting a supreme, ultimate principle, Brahmanical Hinduism – Vedic and Upanishadic / Vedantic –stands for much more (or something different) than the polytheism with which it is often naively associated.
Buddha’s zenith and spiritual ‘enlightenment’
The Buddha attained his ultimate attainment probably in Bihar (the ‘Bodhi’ tree is traditionally located in the locality now called Bodhgaya (which has a latitude of 24° 42′ N, i.e., only 1° from the Tropic! The other 3 major pilgrimage sites for Buddhists (Sarnath, Lumbini and Kushinagar) are also very close to the Tropic.
Buddhism is non-theistic and considers the Hindu concept of Ātman / Brahman as unfounded, affirming that of Emptiness (Śūnyatā). This may seem paradoxical from the perspective of the hypothesis of this study, but it is not! The Buddha denied precisely what was visibly ‘absolutized’ by his tradition. While, by reference to the solar principle, the Brahmins absolutized the Self, considering it the ultimate principle, the Buddha went further with the reasoning by decreeing that the Self is also a phenomenal, illusory manifestation. Buddha can be likened to a modern scholar who asserts that although we think of the Sun as eternal and indestructible, it too is in constant motion and transformation (caught in a ‘Wheel of Becoming’ – to use a Buddhist term) and that at some point he too will be destroyed. Everything came from Nothing and returns to Nothing, the Buddha asserted, in unison with modern physicists.
At the same time, Buddhism is associated with the idea of ’awakening’ and that of ‘enlightenment’ – quintessentially ‘solar’ ideas.
The Sun – a symbol of the Supreme Divine Principle
In ancient times it was hard NOT to associate the Sun with the divine principle! The sun brings light and warmth – therefore life. Although in his diurnal cycle, the Sun ‘dies’ at sunset, he ‘revives’ again at sunrise; though he arrives ‘dead and buried’ at the winter solstice, he ‘rises from the dead’ shortly afterwards, and then appears ‘in glory’ at the vernal equinox – he thus appears to have an eternal, imperishable essence.
The hypothesis I propose here is that the ideas of an ABSOLUTE character related to the SUPREMACY, UNIQUENESS and UNITY of a certain divine principle (and of the Divine Being) probably reflected, among other things, a fact that has a deep symbolic meaning in the regions – very close to the Tropic of Cancer – in which they appeared: the maximum culmination of the Sun (and therefore of its BRIGHTNESS and LIGHT) is reached precisely by its presence at (or very close to) the zenith of the observer (so right ABOVE one’s head, in the HIGHEST place of the sky).
The Sun situated overhead at its solstice culmination means that from above, from the ‘highest’ point of the sky, at midday, radiates the most persistent light… At the Tropic, the Sun not only can reach the highest place but does so when its ability to bring light is maximum! At that time all shadows disappear, Light knows no antithesis, a very significant thing! There the Sun is not just a celestial object at which, in other places, you look (obliquely!) with admiration – beautiful and majestic, perhaps, but still not so elevated -, but becomes THE ONE, THE ONLY ONE worthy of attention, THE ONLY ONE WHO DOMINATES. It perfectly symbolizes THAT WHICH IS ABOVE, THAT WHICH GOVERNS LIFE – it is the symbol of the Divine Light and the Supreme, Absolute Consciousness, it is the ideal to be attained.
Both the world’s first monotheistic cult (the cult of the sun god Aten), the three great Abrahamic religions (Judaism, Christianity, and Islam), and the Indian transcendental religions Brahmanism / Vedanta and Buddhism arose very close to the Tropic of Cancer, where the Sun reaches its zenith on the lightest day of the year, in the true ‘festival of light’.
Is this a significant thing? I think so! I don’t know if anyone else has thought about it this way before, but it could be a very interesting topic for research…
And here are some images simulating the zenithal culmination of the Solstice Sun at Luxor, Mount Sinai and Mecca:
By comparison, let’s look at the same solstice ‘sky’ in Athens and Rome, the two major centers of ancient European polytheism:
 Jan Assmann (1997). Moses the Egyptian: The Memory of Egypt in Western Monotheism. Harvard University Press
 Robbins, Frank E. (ed.) 1940. Tetrabiblos, Book 2, ch. 2; Cambridge, Massachusetts: Harvard University Press (Loeb Classical Library)
 Smith, Mark S. “The Near Eastern Background of Solar Language for Yahweh.” Journal of Biblical Literature, vol. 109, no. 1, 1990, pp. 29–39. JSTOR, www.jstor.org/stable/3267327. Accessed on 13 May 2020.