In the world at the moment, the most popular religions seem to mostly be religions that worship only one "God", such as Christianity and Islam.

However, in the past there were many religions that worshipped a vast number of "Gods", such as Norse, Greek, Roman, Chinese etc.

Is there a historical reason why these older, multi deity relgions were replaced with religions that worshipped a singular god, and if so, when did this occur?

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    Not a historical reason, but if you think about it - polytheism can accept another god; monotheism cannot.
    – Semaphore
    Commented Apr 10, 2015 at 11:13
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    It's worth noting that Christianity insists it is a monotheistic religion by having one God manifest in three persons, but the distinction from a scholarly point of view is certainly debatable.
    – corsiKa
    Commented Apr 10, 2015 at 15:39
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    I disagree with your premise. What is the prevalent religion in China for instance?
    – Jodrell
    Commented Apr 10, 2015 at 16:23
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    Toaism, Bhuddism, Hinduism and indeed Atheism and Agnosticism are all very wide spread theologies that surely rival the popularity of the Monotheistic counterparts.
    – Jodrell
    Commented Apr 10, 2015 at 16:30
  • @MarkC.Wallace - while hardly an historian myself, I do think historical methods are probably applicable, because - at least the case of the monotheisms - religion is primarily a mechanism of social control. Some of the proposed answers mention the spread of the two monotheisms by the sword. They also mention imperialism. I posit that dominance is a direct consequence of the mutual reinforcement of the successes of the society and the religion on their rampages of imperial conquest.
    – Peter Wone
    Commented Apr 10, 2015 at 23:45

6 Answers 6


I'm not sure you can really state that thesis with certainty. The world's top two religions are indeed monotheistic. However, that could just be explained due to them both arising in the same region.

The third and fourth largest religions, Hinduism (1 billion adherents) and Shenisim (about 400 million), are both polytheistic. The fifth, Buddhism (also about 400 million) either has no gods or is polytheistic as well, depending on how you want to look at it. None of these really seem to be in any current danger of being replaced by a monotheistic faith.

One can also make a case that the two large Monotheistic religions were primarily spread by the sword, so its debatable how much their modern success has to do with their own internal qualities. Nearly all countries where Islam is prevalent are either Afro-Asiatic-speaking countries, or were conqured/colonized by Afro-Asiatic speakers during the period they ran the trade routes to the far east and sub-Saharan Africa (and all such countries lie along those trade routes). Nearly all countries where Christianity is prevalent are either Indo-European speaking, or were conquered and/or colonized by Indo-Europeans during their imperialistic age.

So if I were to have to put a time on this... For Islam it would be the 8th to 11th centuries along the spice routes, and the end of that time for sub-Saharan Africa. For Christianity there would be two major periods of expansion: one from the time of Constantine (4th Century) to the end of the Roman Empire (5h Century), some slow progress in Europe after that, and then another that started with the Age of Discovery in the late 15th century, and ended (most likely) with decolonization in the late 20th Century.

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    Fair point. As far as I am aware though, there are far more dead polytheistic religions that there are dead monotheistic religions - I coudln't name a dead monotheistic religion. Commented Apr 10, 2015 at 13:36
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    @DrRDizzle - Just because you haven't heard of something doesn't mean it never existed. Check out Zooastrianisim, and all the Gnostic belief systems. Its quite possible there are many more that came and went with no record. Not that numbers really show a thing here. After all, there are an infinite amount of numbers, but only one 1. So sheer statistics would tell us >1 is far more likely than exactly 1.
    – T.E.D.
    Commented Apr 10, 2015 at 14:38
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    @DrRDizzle How about all the dead branches of Christianity? There's probably more of those alone then the variations of polytheism.
    – rmoore
    Commented Apr 10, 2015 at 15:54
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    @DrRDizzle Atenism. Commented Apr 10, 2015 at 16:24
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    We also have a problem with measuring the actual number of adherents of any religion. As for instance in parts of the US, openly rejecting Christianity may get you socially ostracized. In parts of the Islamic world, it can get you killed. So how many of those who regularly go to church on Sunday or mosque on Friday actually believe?
    – jamesqf
    Commented Apr 10, 2015 at 18:05

One of the main common tenets of Monotheistic worships, is the inherent assertion, that there is only one God; that those who consider otherwise are wrong. Hence, its a motivation that followers should make efforts to bring those who don't recognise their one God, under Him,because they are under the influence of wrong.

Hence, monotheistic religions all over the world, made the efforts to get more and more followers, and hence they got more and more followers.

Polytheistic religions, most often, did not see differences as problems, unless there were steep cultural disparities. People with new Gods, meant , to polytheists, most often, new Gods to be worshipped and added to the pantheon. Simple

  • Not Simple but, it is certainly true that a Monotheistic belief system is concordant with a Feudal or Monarchistic form of government which is likely a more effective for waging otherwise unjustified wars.
    – Jodrell
    Commented Apr 10, 2015 at 16:34
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    Case in point: the Romans would quite happily assimilate the gods of conquered peoples into their own pantheon, either in their own right or as aspects of existing Roman gods.
    – Mark
    Commented Apr 10, 2015 at 21:35

It's odd no one has mentioned Judaism. Arguably the source of both Christianity and Islam, it has (despite occasional attempts) never been very imperialistic.

Also, Sikhism, another monotheistic religion, has not (that I know of) been particularly imperialistic.

On a slightly different topic, if members of two different monotheistic religions discover that they have no major doctrinal differences, can it be said that the religions are truly different? Therefore, isn't it likely that multiple monotheistic religions have merged into just a few over the millennia, especially in the pre-Christian era?


Not getting into the WHY. But take a look at Egyptian religion and history. They were polytheism (http://en.wikipedia.org/wiki/Ancient_Egyptian_religion) transformed into monotheism (http://en.wikipedia.org/wiki/Atenism) and then changed back. Looking at those details and might provide some insight as to the how.

  • This doesn't seem to answer the question: it neither explains when nor why. But it would make a perfectly reasonable comment. Commented Apr 10, 2015 at 18:59

Almost every religion or spiritual belief system in the world has at least some expression of a single god or an underlying force that permeates everything. God in that sense is usually described as omnipresent, unchanging, eternal - that which has always been, always will be and from which everything is created.

For Hindus that would be Brahman, Christians would call that God, in Islam it's Allah, Taoism teaches of Tao and the list could go on. Even in shamanic traditions there is almost always something that is recognized as the underlying force of all existence.

Modern physics has also observed and recognizes such a concept. Physicists nowadays call it the Unified Field Theory.

In polytheistic belief systems the various gods are usually expressions of different aspects of existence.

Monotheistic religions speak of a direct connection that an individual can achieve with god. Perhaps this makes the proposed final reward of monotheistic religions very appealing and the ultimate punishment very frightening. Psychologically this is a far more powerful form of mind control.

Polytheistic religions don't speak of such grand rewards or punishments. The different gods govern various aspects of the world and the believer is left to barter with the gods for good fortune.


If you look at the European area alone, there is a distinct shift towards a more 'modern' monotheistic religious in the rise of the Mystery cults in Greece and Rome. Mithras, Sol Invictus, were somehow different and beyond and more exciting than the old pantheon. Even in standard Paganism, individuals tended more and more to identify with a smaller set of gods as patrons - Jupiter and Hercules for Diocletian and the Tetrarchs. Julian the Apostate's supposed return to Paganism was in a form that standard mythologies would find puzzling, as he imposed a single heirarchy for all pagan gods with one god at the top.

In the midst of this, Christianity gained traction as it also could offer a more personal, active relation between men and the gods than standard Paganism. It won out in this case, but the other cases indicate that Paganism was becoming unsatisfying in general, and an opportunity for a new religion was open.

I would not consider Atenism a new religion, as it was a personal construction of one man and dropped when he died. Even his son dropped it as soon as possible.

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