Religion is often used as a collective political identity regardless of whether people agree with the actual tenets of a religion1. Studies have found that many people join a religion not because they agree with its theological arguments, but because aids their political intentions2. Although rare in modern times, historically when mass conversions saw entire countries convert to a new religion, it nearly always coincided with the faith of a powerful conquering neighbour3. This bodes well for the material wellbeing of newly captured colonies but doesn't give us any positive evidence about whether or not the new religion has a healthy handle on the truth. The modern equivalent sees states like Russia push the Russian Orthodox Church on its people, and China push Taoism. In both cases, as luck would have it, the people en masse find that these organs of the state also happen to represent divine truth. Where those states are influential, there are many believers and where their power is remote, the believers melt away. It's not evidence driving belief, it is politics.
“Some [religious] traditions - or versions of them - attract a system's elites, whereas the rebels in a society have a natural affinity for other religious beliefs or interpretations of the same tradition. Elites in virtually every culture use religious legitimations to explain why they are in control and others are not. Similarly, the most effective dissident movements often employ religious arguments to legitimate their own positions.”
Giving things religious meaning 'gives the struggle an intensity and legitimation otherwise unavailable, and makes it easier for reformers and revolutionaries to mobilize popular support'. Leaders and followers both use religion and religious symbols as social tools. It was used in that way by ancient civilisations' rulers such as those in Egypt5. As long religion can act as an authority or as an anti-authority, groups of people will be called to religious traditions based on their position in society vis-a-vis the powers that be.
Post-Communist Russia dropped its rugged opposition to organized religion, and allowed religious groups to operate again. The result was a revival of interest in religion6,7, causing a statistical tick in a world that is otherwise generally undergoing a process of secularisation (loss of religion). The Russian state pushes Orthodox Christianity, which has proven itself useful as "a tool for reconstructing political and geopolitical identity in a post-Soviet era"8. Without the ideology of the USSR to hold people together, Russia finds that Orthodox Christianity is a rather similar tool, so much so, that all of its traditional battles against human rights, conducted in the name of communism, are now handily conducted in the name of Christian identity, as are other political aims.
“Agadjanian (2006) underscores that 'religion was revived from Soviet oblivion, by both religious and secular camps, as a grand narrative believed to be full of strong symbolic content available for collective identity quests' [and] the same was true in other Eastern Orthodox countries Borowik (2006) underscores that 'in all the Eastern European cases, religion has probably become more important because it offers a tool for reconstructing political and geopolitical identity in a post-Soviet era.”
"The Meaning and Scope of Secularization" by Karel Dobbelaere (2011)8
Christian leaders around the world despaired in horror when in 2022 the Patriarch Kirill, head of the Russian Orthodox church, backed by his high-ranking Christian clergy, preached that the war against Ukraine was a righteous war being fought by that good man Putin for the future of Christianity in Ukraine, repeating official Russian excuses for the invasion.9.
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Some of the greatest shifts in the numbers of religious adherents occur when a community converts en masse from one religion to another in a short period of time. This was common in history, although it is now rare. One single cause of this behaviour stands out as the most common influence that facilitates these events: The threat of a conquering enemy.
“Spain and Portugal, for example, took over all of Latin America, and with their armies came their established church, Roman Catholicism. Spain also conquered the Philippines in the South Pacific, thus putting Catholicism in place there, too. Great Britain had the most far-reaching set of colonies - in North America, Asia and Africa [...] all of which were influenced by Anglicanism, Britain's established Church. In like fashion, the Dutch exported the Reformed tradition, Russia its Orthodox tradition, and so forth.”
"Religion and the State" by Phillip E. Hammond and David W. Machacek (2011)3
It just so happens that mass conversions are nearly always of the kind that convert the populace to the same religion or denomination as a new encroaching power. This bodes well for the material wellbeing of newly captured colonies, but, it does not indicate any positive evidence towards the overall truth of the religion's doctrine and beliefs. And if in doubt, consider, what happens to those who fail to convert? Slavery, subjugation and the massacre of natives plagued the imperial age across the globe. The expansion of world religions should be based on individual's evaluation of the evidence for the religion's claims, but in reality, such a cool approach is very rare. Power games have converted more souls than faith ever did.