Hello there. This is my first ever reddit post, let alone answer in this sub. I hope I do it correctly and meaningfully. For the question about corruption, I am going to use basically one book +: The Byzantine Republic, by Anthony Kaldellis. I don’t have it with me right now, but I will have it tomorrow (along with some more on the subject), I can edit it or add specific citations and page numbers.

There are two different questions in your post, linked by the Varangian Guard. I will try to link both answers using the same imperial security force, as it will make total utilitarian sense.

I can get where the term “corruption” came from in the context of a documentary, but your definition of it, “many different groups of political people that was together” could be more defined plainly as politics, corruption being just one of the instruments of politics. Constantinople had a very complex and active political system, with different groups (may them be based on wealth, class, political tendency, religious ideas…) acting together or against each other to advance their interest. As Kaldellis states and proves in his book, the political organization that took shape in Nova Roma-Constantinople after the crisis of the III Century came to be as urban as it was in Old Rome and, more important, as populist, or Republican, as it had been during the times of the principate, when “emperors” where seen, thought of and sold as ultimately “overseers” of the state, making sure it worked for the benefice of the rex publica. Kaldellis points to the greek translation (or adoption of an ancient word) the eastern romans used, politeia. He points in his book, using various sources, how “the wellbeing of the politeia” was the cornerstone of “byzantine” ideology; he compares it to democracy today. Everybody knows most politicians don’t have the betterment of the common people, or democracy as a system, in mind, but no sane candidate would state elitist or anti-democratic views publicly as it’d mean political death. The same applied to the emperor of the romans; he might work for his own pleasure and the betterment of his friends, family and associates, but he (or she, as there were some sole female rulers) needed not to be percieved as doing such; in Constantinople, political death meant uprising and, most of the time, deposition. This, of course, comes in plain confrontation with the oficial narrative of the emperor being a quasi sacred figure, God’s regent on Earth and all that. Constantinople was the capital of a very complex state and society, and thus a very complex view of political legitimacy. Legitimacy rested on popular consensus, that all (or most) of the groups of the politeia were pleased. When some weren’t, political rivals could use the situation to their advantage. The roman people were not alien to idea of an emperor being deposed; on the contrary, sometimes the regular people had a collective decisive impact on some proclamations, and they were present as an important actor in all of them. I am not, at all, trying to make the point of the constatinopolitan regime being a democracy, as it wasn’t by any means, but it was in some way a very populist system, meaning that political legitimacy didn’t rest on weapons, name, class or even race; the most important thing was to, at least, be percieved as working for the common good. I made this point just to show how complex the political scene was, specially before islam, were the populations of the great eastern cities (alexandria and all) exerted their fair share of populism and social comentary. The stuff of power being fought over about is called politics, and politics did happen, all the time, in Constantinople. It is frankly shocking how a political system had so many violent changes of ruler over so many centuries and still none of those rebellions changed much about how the system actually worked. For Kaldellis, political instability is the manifestation of the republican ideology of the romans of constantinople. I will be able to quote extensively tomorrow.

The fact that legitimacy rested on such a volatile concept such as popularity meant that the emperor’s seat was never secured, let alone his blood; no dynastic system could ever be created, no emperor could rule as a despot for long, before some factions of society (or all of them during some hippodrome spectacle) would actively plot, or suddenly rise, and overthrow them. Kaldellis states the exact numbers, but basically he proves how it is statistically easier for a current US senator to win the reelection that it was for the emperor to keep the throne given the number of uprisings, specially successful ones. You might be familiar with the Nika riots in times of Justinian, and how it all went. He was one of the very few emperors who didn’t fall after a popular uprising, and the way for doing so was to use the army to kill thousands of people. Most emperors didn’t have the guts, the power or the man to massacre the population of the city, so they tried super hard not to get the people angry to the point of open rebelion, which was never very remote anyway.

In this context, corruption can mean two different things: the use of wealth to achieve political dominance and the use of public resources to do it. The first thing was a reality, not decisive but true: the wealthier you were, the better you could buy your way to power, sometimes in acts meant to increase your popularity, others by buying off rivals or paying for favors. That was not viewed as evil, and it wasn’t necessarily considered “corruption”. On the other hand, Constantinople had a very strong state system were social and, most specially, political mobility was achievable, and personal wealth was not a primordial necessity to enter the game of politics. Calling “the absolute power of money” corruption by today’s standards is another topic.

What was certainly not popular was the second meaning of corruption. There was a clear popular idea that the State belonged to all the people and not the current Emperor; some writers go as far as to remind the current or future emperor of the public property of the Sacred Palace; Kaldellis states that the Emperor, thus, was some short of head of the functionaries, having a duty to serve and a dictated (not written but universally acepted) way to do it. There’s even evidence of one actual emperor who was made to swear the position in public, promising to put aside all his personal and familiar interests and work for the betterment of the politeia, almost as a modern president would do, and as a monarch doesn’t by pure definition. And, legitimacy resting on popularity, making fradulent use of imperial wealth, property or court positions was considered corruption or, if not named corruption, it was highly unpopular, and the emperor who openly did this would be critizised, even during prayers in the Hagia Sophia. Missmanagement of state wealth and property it is usually mentioned, post fact, as a justification in some coups.

That position of weakness exposed emperors to great dangers, not only when in public, most specially, when in the palace. The Varangian Guard was created as a body of foreign mercenaries focused on the protection of the emperor, to whom only they were loyal, lacking other political or familiar allegiances. It could be said that the ottoman sultans took the idea to a more complex level with the jenizaries system, but the idea was the same: keeping a military body that was loyal to the emperor only and out of other military structures that might be controlled by political rivals.

And here the answer of the second question. It won’t be very deep as I’m no expert in the reign of Basil II, but he was a very popular ruler, specially among the lower classes, specially the army and the peasantry. The army loved him not only because he was a man of arms (probably the most famous of the soldier-emperors along with Herakleio), but because he acted like them: he dressed like them, spoke like them, even ate the same army rations as them. He made a point of taking the orphans of his soldiers into his protection, and those ended up forming the chore of an extremely loyal army. As for the peasants, he was well liked because he fought the powerful landowners of Asia Minor to attain power, and legislated against their interest as emperor; some of those lands were divided and given to families. This gave the rural peasantry reasons to rejoice: they could stop being oppressed by robber landowners and start being oppressed by tax collectors while investing their newly acquired free time in making future soldiers for Basil. So, to answer your question: He paid the Guard, and everything else, with the public treasury, which had been kind of expanded by fighting against a very wealthy, but unpopular, minority; this was good for the state treasure and the popularity of Basil among non-super-wealthy-landowners. Then he used that wealth to improve the life conditions and rights of the producing classes, which in turn gave him a solid base of taxpayers (which he didn’t have before with the elite landowners refusing to pay taxes) and a great demographic picture for his future military expansion, which in turn gave him even more popularity. I don’t know whether he used the Varangian Guard to torture political opponents in a cruel, vicious way, but he was a very popular emperor at his time and was always regarded as such; even centuries later he was still considered as a good and fair ruler, having only failed at securing a succession-continuation of his regime.

I hope that was useful. I will post quotations and further sources if requested (¿maybe by moderators?) tomorrow.