This is an adjustment of your theory that religion was invented for population control: You now state that religion was used as population control tool.
I would surprise myself if I said the former, if I did, I always meant the latter.
However, there are flaws in this theory too. One of the flaws being that religion may indeed have been considered as possible power tool; it hardly served that purpose well.
Let us take Christianity as an example. Christianity was for centuries a resistance religion, a religion fiercely persecuted by the Romans.
My posts were directed at dominant religions being political powerhouses and serving as unifying force behind a leader, making nation united and stronger. I'm not sure why you want to discuss the beginning of christianity, or christianity in particular, when obviously it wasn't in dominant position yet? It was more destructive to unity of Roman Empire or Jewish people than anything.
Once adopted by the local powers it proved hard to control, especially since much of its mythology - the Vitae of saints specifically - cherished the martyrs of that resistance.
It doesn't matter, they died for Christian faith and same god, a very unifying aspect for all faithful. How destructive was the cult of revolutionaries like Lenin of Stalin for unity of Soviet Empire?
Emperors sought to control the church, the church - especially since it considered the empire bequeathed to itself after the fall of the latest West-Roman emperor - sought to control the emperors and both sought to control the popular movements.
Nobody says that relationship between christian church with kings and emperors were perfect, and it doesn't mean it didn't work well for both sides for most of the time. Obviously if a leader of a country is not a head of a church then we have two strong political centers, and a stage for conflicts. In many cases church was richer than kings and was biggest land and property owner in the country. Church controlled politics and kings, and was the controlling and ruling force for the whole society. To avoid this many leaders chose to separate from Vatican and became their church leaders at same time like king of England, Russian Tzar, and many others. In other cases monarchs and bishops realized that both sides gain more if they cooperate. Most of feudal history of Europe shows great cooperation of kings and bishops.
Kings went to war, and the troops were always blessed by priests: "In the name of God and the King". It doesn't matter if it is in Middle Ages, Germany WW2, recent Balkan war or Aztec Empire.
These popular movements that sprung from Christianity were rather revolutionary, as numerous heretical and semi-heretical movements in the Middle Ages show. The novel "The Name of the Rose" may be fiction but Umberto Eco did very good research for it, and you should read it to get an idea of the revolutionary spirit of several christian movements in the second part of the Middle Ages.
As another example may serve Thomas Becket, who was a loyal chancellor of Henry II Plantagenet. Henry appointed him Archbishop of Canterbury - this is the part that you may consider in accordance with your theory that powers try to rule via religion - in the believe that Thomas Beckets loyalty would remain to Henry. However, Thomas Becket found that he now served God rather than the king and became a very vocal moral critic of the king.
Of course religion have many more functions than political, centralized power, and control of populous, although these are more important forces for religions, being such powerful in history of humankind. Most of all, for ordinary citizens it is an outlet for their spirituality (genetic part of faith), to feel god. Furthermore, people go to the temples for social aspect of being and interacting with others, they sing, they pray, they talk intimately with gods about every little thing in life, they ask for help, they thank for everything, ask for good life after death, offer their suffering in good intentions, they ask for forgiveness and acceptance. From psychological point of view it is very therapeutic for any person. Also religious communities act as social net for the most unfortunate or anyone needing help.
if not a distortion, of history.
Can you explain what is the main cause for separation of state and church embedded in our modern constitutions?
Can you give examples from the past when kings went against church, and what were the consequences for them of such actions?
Why so many monarchs chose to become leaders of dominant religions in their countries, in Europe and around the planet?
What happened to king Tut in Egypt when he went against dominant religion?
Should we mention Teutonic Knights, ultimate power, as ruler, warrior, priest, rich land owner, and a spiritual leader.
PS. I'm not saying and never did that christianity as a religion is anything special, better of worse than others, in mentioned aspects, and as dominant religion.
PS. Here is what I mean by Spirituality.
http://www.eupedia.com/forum/threads/28375-Beliefs-Spirituality-and-why-we-believe