If you wanted to do a complete historical disection of mass population control you would first start with identifying the "reins of power".
Ancient Greece
Those that seemed to have contact and favour with the gods were held with the upmost respect. Many kings had Seers and even travelled to see the Oracle.
The Oracle and their kin of course knew that they would be invited to audience with many kings and their messengers, so the ability to play one off the other arised many times. This would suggest that the Oracle at that point was no more mystical than you or I, just very clever at deception and manipulation.
Christianity
The following will seem unfounded by some, however I believe it's an accurate depiction of events when this particular religion was founded.
First a man of a poor decent want to change his way of life and that of others that had his hardships. He decided to express his tales of woe and plans in stories to people that would listen perhaps in a local market place and rivaling the site that could be seen at Hyde Park's "Speakers corner" in London.
Eventually he makes friends with people that see how they can change their way of life for themselves and others (imagine such people aren't poverish, they are also apposed to having the influences of Rome dictate how their own country runs)
With that the group emerges and a plot to gain power from numbers and money from those that are willing to support their cause. The "Leader" tells them to spread some doctorines far and wide, and such doctorines are seeded to be taught and "easy listening" in the sense of gaining support. Such doctorines and stories merged some inttuative material with just material that would capture the imagination and cause the stories to be spread. As stories do however, some of the facts are vastly exaggerated and their leader no longer comes from humble stock but is their messiah to their religion with unquestionable sightings of unnatural feats.
Any new followers give coin to the "cult", and the money accumiliates allowing for new shrines to be built in new cities across the empire. With each province however came people that spoke different languages and dialects, this meant that the doctorines had to be converted to allow the best interpretation per province.
Rome eventually takes note when the new "cult religion" has massed a following and reports of the number of shrines across the empire start to circulate within closed chambers. Such Cult group could be a political assassination of Roman policies and Order which of course can't be tolerated by the leader of the day.
The Roman Caesar decides to find out who the leader is of this Cult group and have him put to death in one of their most painful ways imaginable to make an example out of him to all that followed him.
However the followers of that cult weren't so easily supressed, they utilised the death of their leader as a Martyred example, both disinformation throughout their religious order and the removal of their leaders body for fear other rival religions would parade it caused yet more stories to spread across the empire and of course Unrest within the provinces of Rome.
Roman Empire
As history dictates the Rise of Rome, meant the assimilation of many different cultures and countries. Such assimilation meant unrest, unrest due to people being enslaved or not taking kindly to becoming "new citizens of Rome".
For those provinces successfully controlled by Rome, the people continued to have their beliefs, religions and traditions. The problem was that for a vast empire of multiple provinces to survive, the differences within each province had to be put to rest.
Such differences if not "nipped in the bud" could eventually spin out of control, for instance if two opposing religions "argued" their doctorines it could rise to bloodshed, which depending on the size of the religion could spread right across the Roman empire.
It's suggested that the installment of a monothesitistic religion based upon it's accumiliated power-base and unrivaled stories created based upon the martyring of it's founder was enough to settle most of the conflicts over time, and bring stability to the empire at that time.
It wasn't that the Roman Caesar of that time believed in the religion, but saw what "control" that religion had over it's devout followers. Allowing one religion over all others also broke down religious disputes within Rome, only leaving disputes with Empires not of Rome.
Julius Caesar
I'm not going to go to great detail on the times of Julius, however his demise was caused by the Roman Senate and their "Deception".
Epilogue
All that I have mentioned are before times of High-Tech equipment and high-tech power struggles, My reason is just to prove that Control/Manipulation of people and corruption in power has been a human trait from Ancient times that seemingly has never been over thrown.
Perhaps one day people will wake up to find out that the only truly free society is one that doesn't keep secrets and is truthful about it's operations. However with much to be lost by the corrupt (like power and money) from having to be legit, it will alas be nothing more than a proposed freedom.