If you will decide to read this book (which I do recommend), you will find the definition of "theoria" in the following rumination:
"Yes, fame and good name were loved, competition was admired, and the pursuit of gold and silver was never condemned outright. Nevertheless, the highest esteem was reserved for a life devoted to contemplation, that is, the selfless pursuit of truth. Any truth in any area of life. In Greek, this kind of mental pursuit was called theoria. Originally, the word referred to every act of contemplation— contemplation of any phenomena; later, it came to refer to the official state missions sent to the sacred games to witness them and worship the gods; and eventually, it came to pick out the just described intellectual attitude: not only a mind directed towards great and abstract matters; but also, its fruit. It is in this last sense that the word lives to this day."
So yes - I think this book is ultimately a contemplation of the "swan song" of the glory of the Roman Empire in the fourth century, the pursuit from surviving documents ("not all of them fully credible") of the truth about a civilization gone forever, as "in every epoch, individuals emerge who wish to trace the course and meaning of the meanders of the capricious river, conventionally known as the historical process, descending from the dark and unexplored mountains of its origins and flowing towards an unknown ocean of the misty future." (so poetic a metaphor -I couldn't resist it!)
Today, we Europeans live in a democracy, and I wonder if its peak (like the peak of antiquity) is not somehow slipping unobserved behind us. The world is becoming more brutal, the intellectual pursuits are becoming unfashionable compared to gaming, clubbing and social media; the rich, strong and ruthless are the most admired, and the "selfless pursuit of truth" becomes uninteresting and undesirable, what's good and right shrinking under the miasma of a multitude of selfish wars.
We find out about those times that a wide middle-class, which was both the flower and the foundation of the Roman Empire in its era of greatest splendor, looked up to liberal thinkers and philosophers, and worshipers of many gods lived in harmony. "They liked games and baths, they knew their literature quite well; they maintained their old traditions, both local and national. For various reasons, they often undertook long journeys in the many lands of their vast empire , whose participating members they felt themselves to be. They believed in dreams, omens, prophets, and gods (in this order)." There was an enlightened and liberal separation between scholarship and faith, and women had access both to baths and to erudition.
And then, in an empire which used to be a republic, politics and greed used religious fanaticism to tear it apart. Those became very sad times, in which justice did not rule, assassins walked free and looting was disguised as destruction.
Can you imagine that day of games, when the crowd packed the hippodrome to enjoy chariot races, and a cordon of soldiers surrounded the building to murder seven thousand unarmed civilians within three hours, and according to other sources fifteen thousand, almost exclusively men? And "the officers made sure that their soldiers took pity on no one."
Or how a woman who gained fame as an expert on the teachings of various philosophical schools, widely respected for her erudition, was designated the scapegoat as a blasphemer, and dragged to one of the churches by a frenzied mob, her dress was torn off her , and in a frenzy of rage, she was cut to pieces, and her remains were burnt so that no trace would remain of the blasphemer?
Or what was Tatianus’s fate? He was repaid for his loyal service as a high official of the empire with the execution of his son in front of his eyes, and losing everything but his life. He was eventually pardoned, but his property was confiscated, and he was exiled and died of old age, supposedly blind, some say living like a beggar.
"The singer takes the place of the philosopher, the rhetorician has been replaced by a teacher of amusing tricks. They lock their libraries up like tombs. Instead, they have water organs prepared, cart-sized lyres, flutes, and all kinds of actors’ equipment.” And:
"In the course of every show, it seems, people hired to applaud stand up and shout in praise of this or that animal tamer, charioteer, or actor of some kind, but also in praise of officials, both high and low; why, even of matrons. And the exclamation is this: ‘Let others learn from you!’ Yet no one says what is to be learned.”
Here we have a writhing snake pit of evil, fanaticism, and hatred, in which both the adherents of the religion of love and the worshipers of the ancient gods had blood on their hands. "Furthermore, that the great propaganda power of selfless devotion to a worthy ideal, which had contributed so enormously to the early expansion of Christianity, had to gradually lose its efficacy as men of lesser ideological commitment joined the victor’s camp for self-interested reasons."
There is a trove of information about those times, which don't seem to me so different from ours. Each reader must chew the words for himself, ponder on the information and draw his own conclusions, so I hope you are intrigued enough to read this book.