Religion and politics are seemingly always on a collision course of some kind. In the early times of emerging civilization, the pantheon was littered with imaginative constructs and awe-inspired influences. Astronomy students may recall the eastern star Sirius, whose appearance signaled the flood seasons for ancient Egyptians. The men who were tasked with knowing this correlation and observing the heavens throughout the seasons so that they might report the news of the event were essentially the priests of their day. In a very real sense, this kind of knowledge was invaluable to the common people, and the prestige of these early astronomers gave them the rare political position as intermediaries with the Gods themselves.
The Gods began this way, as distant, remote conceptualized beings associated with the ills or blessings of nature. Even the tough and thuggish Spartans were required to consult with the oracle before engaging in battle. The Pantheon is replete with examples of isolated situations for which the guidance of the divine was a survival tool. But where Egypt and Greece, and ultimately Rome, differ is not their understanding of theology, but rather their views of the relationship between the ordinary people and the systems of government which presided over them. The Egyptians were fine with worshiping an all-powerful man-god. The Greeks and Romans? Not so much.
The virtue of these two later cultures held that the people themselves should have some role in the government; after all, these people supplied the soldiers that defended the government, or conquered for it! The path from Egypt to Rome is the pursuit of that relationship, wherein a person's life has value, their rights are to be protected, and they have a voice in what goes on. The transition from autocracy to democracy(of any kind) is like an open mouth getting wider and wider. The pharaoh needed no senate, but in 509 BC, after the amoral exploits of Sextus, "the Romans...vowed they would never submit to another King."
The Senate, and the empire it must govern, had both grown significantly in scope over the 800 years that followed, and though it was not always what it seemed, the Roman political machine found in rulers like Octavius some working balance between peace and freedom. In doing so, however, they lost a little bit of their power and influence along the way, as is so often the case with imperialist societies, The appointments of special commanders and provincial commanders to solve problems would begin the downfall of their civilization. Where the Greek and Roman civilizations had struggled so hard for so long to move away from pure autocracy, these short-sighted mistakes would create the dependent political climate that made the reign of Diocletian possible, if not inevitable.
Like the Pharaoh, Diocletian displayed no illusions of democratic ideology. He insisted that his subordinates kneel to him in deference, as though he were God Himself. Regardless of the military strength that brought him to power, this model was in direct opposition to the values of the Romans, and the many others before them. These were not Atheistic people, without superstition or fear of the All-mighty, but they were very attached to their understanding of liberty. To deny them the freedoms and involved political culture to which they had become accustomed was to shatter the very stones with which the city was built. Sure, Augustus was perhaps as much of a autocrat as Diocletian, but he had the good sense not to throw it in his people's faces.
Diocletian's power did not in fact originate with any supreme being. His authority was instead sanctioned by military strength. Where prior rulers had sought to reduce the military, he doubled it to pretect that authority, straining a treasury that couldn't bare the weight. When the economy dwindled as a result of the gross Chinese net-import, his Edict of Prices illustrated his deluded sense of control. When the money, which had once flowed like milk and honey for more scrupulous rulers, finally ran out, he turned to confiscation to pay the bills. There is simply no better way to alienate everyone around! Loyalty and Respect are the glue that held the empire together. Diocletian required worship of his subjects, but gave no thought to their own needs and aspirations, and so had no cause to rightly expect that loyalty to remain in-tact. Without freedom, there would be no more Rome, at least not as it had been. The Empire crumbled. It is not surprising that his successor Constantine was able to consummate the marriage of church and state: Constantine wouldn't try to be a God, but he quickly realized how useful it is to have the right God in your pocket at the right time. In his wake, for seventeen centuries, there has followed a sea of endless tragedy. What could have been the flower of Democracy simply grew thorns instead.
This is the danger of the invisible monarchy: it never stays invisible.
Image Source: http://flickrhivemind.net/Tags/egyptian,wwwbrooklynmuseumorg/Interesting