Allow me to apologize in advance; you are bringing up topics that I love dearly, Z. Being given the opportunity to talk about the Medieval Period is like being given an early Christmas present. I will try to restrain my enthusiasm, but... *gleeful squeal*
... allowing the Byzantine empire (whose civilization was far ahead of that of Europe) to crumble to the Turks...
Allowing? Interesting proposal... yes, I believe that could be a very interesting argument. Certainly, the west could have done more to help, but keep in mind that it was not unified by anything that could lead them against the Turks other than religion. The Byzantine Emperors and Patriarchs were seldom on good terms with the Papacy. While this did have very heavy religious overtones and sources (thus, one could say, being the fault of religion), it was also a battle between capitols. Rome looked down on the upstart Constantinople, and Constantinople looked down on the decrepit Rome. There were two cities in the Empire that gave out monthly grain allotments to the citizenry: Rome and Constantinople. The latter supplied it by means of the royal coffers, the former used to do that until the western empire began to decline, and then it was the church that took over. People didn’t look kindly at the Emperor for letting them starve.
Then there was the interference of Emperor Justinian and his general, Belisarius. In attempting to "restore the Roman empire," they ruined much of the remaining infrastructure in the west. The last dregs of ruin around Rome itself were not fully restored until under Mussolini, over a thousand years later. While the west could have aided the Eastern Byzantine, the east did very little to encourage goodwill. Indeed, even after the west did send aid, prejudice prevented it from being effective. The western generals were seen as country bumpkins, and the eastern leaders were seen as fancy-pants good for nothings who couldn't be trusted to try to keep the western soldiers alive (a belief not without cause).
Of course, while the west could have offered support, the question is how effective would that support have been. Gone were the standing armies of the Roman empire, wasted away in internal political struggles between this or that would-be Emperor. The east was capable of raising new armies, since they had the funds, but the west? That depended on the good will of local lords (who might listen to the Papacy when they had to, but don't mistake a common religion for a common allegiance). The military system of the west wasn't conducive to long-range campaigns. Rulers could call up an army as a form of taxation. Well-to-do's paid the rulers in a number of months of military service a year. After that time was up, the soldiers were free to return to their own lands. In a time when war could only be fought for a small portion of the year, and when your army couldn’t be trusted to remain until the fighting was done (just until their yearly obligation was fulfilled), the ability to project power from the west to the east was very small. Individual rulers, knights, and soldiers had to want to travel to the east of their own accord, not just because the Eastern Emperor asked them to.
It wasn't until the First Crusade (which is an anachronistic name, as the word itself comes from the third one) that this really began to happen. And keep in mind, the first Crusade was successful. Of course, just as the Muslims expanded into Europe in the wake of a power gap, so too did the First Crusade come at a time of weakness of the rulers. Religiously speaking, it was an armed pilgrimage. Those going were only supposed to visit the holy sites in the regions; the weapons were in case someone tried to stop them. Political ambition, however, took advantage of the religious fervor so that Crusading states were established, instead of left in the hands of the current rulers or given back to the Eastern Empire. Even when the west helped, it wasn't really the help the Emperor in Constantinople wanted.
So yes, the west could have helped the east more, but they had little cause to do so, and they had their own agenda. That is hardly any different than modern political affairs, to my understanding.
As a side note, while the Crusades were hardly a sparkling point in the history of religion, they too were a necessary step in the development of modern society. As the crusaders went to the east and returned, they told tales of the civilization they saw there. They brought back spices, books on medicine, law, philosophy, etc. There is a reason the renaissance hit Italy first and it had very little to do with it once being Rome; it was because Italy was the point of contact between the east and the west that the Crusades established.
... claiming dominion over every secular affair in Europe with that certain Papal Bull…
Well to be fair, the Catholic Church was largely already doing that. It started with secular governments being unable to take care of things, and so the Church stepped up. Grain, building repair, public works, etc. When secular courts faltered, people turned to the ecclesiastical courts for help. Classical Romans started the tradition of having the Church crown Emperors, but even that wasn’t the origin of the idea that temporal power was subject to spiritual authority. Given that Roman Emperors were deified, worldly power already had a religious tint.
... encouraging that the Black Death was a spiritual punishment...
True, but keep in mind that this had been going on long before the Middle Ages. The Greeks believed this (the Iliad centers around it!), as did the very religious Romans. It is a fancy that the Classical period was even mildly free of religion; the Romans involved it in everything.
... ingratiating the clergy into European civilization ...
Given that the clergy were usually the most well educated people of the day, the political leaders wanted them and they needed them. The Church tended to be only too happy to oblige the secular authorities.
Ah, but the preservation of secular works is not a Christian phenomenon.
Very true, but all the secular people in the west who would have preserved secular works were dying and or moving to the east. The Germans didn't know enough yet to save the books themselves, and so the task fell to the Church. One would really have needed the Roman Empire to have not fallen in the west for the Monasteries to have been unnecessary. But before I move onto that very interesting topic, there is one other note:
Serfs and most people couldn't read or write in the Medieval ages, and so priests could make up whatever spiritual assertions and interpretations they desired when dealing with lower classes.
Most people couldn’t read or write in ANY age; the middle ages were hardly unique in that regard. Of course, often even the local priest couldn’t read or write. And yes, when the populace can’t read (and when things aren’t written down), that invites exploitation. This is why written laws freely available to a literate public is always a turning point in history, be it the Magna Carta or the 12 Tables of Rome (which likewise prevented the secular aristocrats from altering the laws to suit their needs).
Besides, if Greek-based western civilization had never fallen in Rome, would we have needed a revival a thousand years later to pick up where we left off?
“How the world might be different if the Roman Empire in the west never collapsed” is a terribly interesting question. Unfortunately, entire books can easily be written about much simple counterfactual histories (and they have been), so anything I say here must inherently be extremely abridged. Of course, counterfactual histories are also incredibly difficult to write, requiring an intense understanding of historical processes that even few historians possess. In 20 or 30 years I might be able to write a good analysis, but for now hopefully this will be vaguely passable.
The first step is to identify what would have happened differently for the Western Roman Empire to have not collapsed. The Middle Ages are usually said to have started in the 5th century with either the fall of Rome-the-city and the murder of Romulus Augustus, but we actually would have to go further back. Even if those two events didn’t happen, the Roman Empire in the west was basically gone and events would have progressed largely unchanged. The problem is, even as early as 9 C.E. (and possibly even earlier), the western empire was heading in that direction. Preserving the armies, I propose, would be a good first step in saving western Rome, which means that there would have needed to be a lot less in-fighting. As that was a fault of character in the Roman leaders, I can’t see a way that could have been avoided, but let us say that it was. If the military remained strong in the west and the east, rather than being wasted away in wars with each other, Persia, and the Germans, then both halves of the Empire would have been far more stable.
This would have resulted in many events turning out differently. Islam wouldn’t have had a power vacuum to expand into, so the Turks would have never really had a chance to become a threat to the East. The Germans would have been contained to the far-side of the Danube, though stopping all raiding would have been out of the question (one would have needed an “iron curtain,” as it were, to have truly stopped it). But they would have been drastically reduced.
Right there the modern world would have been vastly different. Mathematics would probably take one of the biggest hits. Not because the Middle Ages were fantastic with numbers, or that the Romans were morons with them. Nope, it is something far more fundamental than that: Roman numerals suck. Sure, it isn’t that bad to write 37 in “Latin”: XXXVII. But what about 299,792,458 (the speed of light in meters per second)? Without the advances made by the Turkish empires resulting from the explosion of Islam out of the Arabian Peninsula, it is unlikely the Romans would have adopted their numerals (at least, not for a very long time).
Without Arabic Numerals, all science would suffer. It is thus quite possible that we wouldn’t have landed on the moon yet. Economics would be a nasty step behind in development as well.
Government would also be incredibly different. Even before Augustus, control of Rome was gained by controlling the military. As such, Emperors were often killed by their own guards, simply because the military was swayed by someone else. The feudal system that developed in northern Europe during the Middle Ages was actually a barrier against this. Military power became dispersed, residing in local lords on whom greater lords could call upon. However, the soldiers were loyal not to the “ruler” of their nation, but the rulers of their immediate homes. This isn’t to say that military coups never happened, but the passing of leadership began to depend on a lot more than who could bribe the Imperial Guard.
True, such a dispersion of military authority happened elsewhere in the world, but not in Rome. If Rome hadn’t fallen, our government would likely still be determined by the military (course, our government wouldn’t be the American, Canadian, Australian, etc government either). One of the great advancements of the modern western world is how peaceful our transitions of power are. We cannot thank the Romans for that one.
We’d probably also not have representative forms of government. It is an anachronism to say that either the Greeks or the Romans practiced democracy or even what we’d call republicanism. During the Roman Republic the aristocrats did control the government, but they were such a small group of individuals that “oligarchy” may be a more proper name for it. It would be horribly hasty and improper of me to attribute modern representative governments entirely to the Germans, but their “Things” (governing bodies of all free-men) were an important influence. Look at the Eastern Roman Empire (Byzantium): democracy did not flourish there, though in them the Roman Empire (with heavy Greek influence!) lasted for several more centuries. Universal suffrage is one of the many byproducts of the fall of the Western Roman Empire and the Middle Ages.
Our court systems would also be different. Trial by Jury is a German institution (well, one that grew out of Germanic institutions), not a Roman one. It finds its origin, again, in the Germanic Thing, where disputes were often brought to be judged before the people gathered there. A good deal of quackery was involved (the “ordeal” also being a Germanic invention), but it was also so in the Roman legal system (where a flock of birds could change a verdict). Trial by Jury is just one part of the modern legal system, though. In total, we do owe a great deal to the Romans, particularly doe to the Justinian Code… though if the Empire had been stable, Justinian likely would not have risen to power, the Justinian Code wouldn’t have been created, and the legal system would still be a mess.
Now one might simply suppose that the Germans could have continued to benefit Western society outside the Roman Empire. Unfortunately, that would have been unlikely. Just as I claim that the Modern World needed the Middle Ages, I would also claim that it needed the Roman Empire. Civilization benefited from the mixing of Roman and German culture. If the western empire wouldn’t have fallen, the Germans would have never moved into the area and become Romanized. They would have continued to develop on their side of the Danube, but the infusion of the civilizing influences of the Romans would have been greatly hampered. Germanic governments would have remained unstable for longer (as expansion into the Roman Empire was the result of forced migration; it operated to an extent in the same manner as the “Wild West” in the United States). However, it is difficult to suppose the course from there. A significant contributing factor to the Romanization of the Germans was Christian Missionaries. Sure, they brought a religion you aren’t fond of, Z, but they also brought Latin ideas. The Law Codes of Aethelbert of Kent, for example, are directly a by-product of the influences of Luidhard (his Christian wife’s chaplain) and St. Augustine (of Canterbury, not Hippo). It takes the form of Latin law codes, but England at that time had no Latin legal tradition from which to draw. Of course, the laws themselves also have a very Anglo-Saxon tint to them, but the point being, the laws came with the cross, as it were. Without a declining Roman Emperor, who knows if there would have been such missionaries. Rome would have had less influence, as the other Patriarch would have still been around to combat it, and thus it would have had less power to send out missionaries, and in turn there would have been fewer missionaries bringing Latin culture with them.
There is a good chance that, without the fall of the western Roman empire, we wouldn’t have the movable type printing press, either. Even if we take religion out of the picture, the problem comes in who created it. Gutenberg is a curiously Germanic name! His life would have been nothing like the one that produced the printing press (assuming he would have been born at all). In time, surely someone else would have produced the invention, maybe, but the Romans were not known as inventors; they excelled at adopting technology and ideas from other people, and in organizing things, but a Roman inventor of movable type is quite unlikely.
We also wouldn’t have Nicholas Copernicus, Sir Francis Bacon, Johannes Kepler, Rene Descartes, Isaac Newton, Robert Boyle, Michael Faraday, Gregor Mendel, William Thomson Kelvin, or Max Planck! Well, a few of them might have been around, if we were lucky, but they wouldn’t have lived the lives they did or produced the works they did, because they all have Germanic heritage. Certainly over the centuries Germans would have moved into Roman lands through basic migration, but they would have been persecuted. The Romans were hardly free of prejudice, and Germans tended to be thought of as dumb, incompetent, unrefined, and child-like. Even if these men tried to give the same call of reason that they did in our history, it is far more likely they would have been ignored under a continuing Roman Empire.
It would be incorrect to suppose that if it weren’t for the Middle Ages, religion would not have had as significant hold on society as it did. The Christian religion started in the Classical period, but even if we remove that, the Romans themselves were intensely religious. They too rejected certain concepts or actions because they might offend the gods, but religion was even more ingrained in their lives. For an act as simple as a child walking they had at least three gods they’d pray to and give sacrifices (a god of rising, a god of standing, and a god of bone development). If you wanted to conduct a business deal, you’d pray to the gods and look for omens. Sneezing could change the price of grain, or make the deal fall through all together! While the Christian Church might have claimed that the plague was punishment from God, so too would the non-Christian Romans have done the same (except they’d probably consult the Sibylline Books and end up sacrificing a Gaulic couple and a Greek couple to appease the gods).
Christianity actually could be said to have reduced the infiltration of Religion in everyday life (at first, at least). Worshipping one God instead of a multitude (including unknown gods, since the Romans were very careful about that) at least saves effort, and though the Saints eventually came to replace many of the minor gods that were discarded at first, it was generally less obtrusive. It was still a part of daily life, but one could at least plow a field or harvest crops without worrying about offending the gods. Mundane actions became the province of humanity again… and other superstitions quickly took it back.
This is getting to be rather long, so allow me to offer one last point. If you want to see the glory of what history might have looked like if the Roman Empire hadn’t fallen in the west, then look to the East. The Eastern Empire failed to produce great enlightenment like the Middle Ages did (even though in doing so, we stop counting it as the Middle Ages); even with the setbacks caused by the fall of the west, if the Greek-Influenced Roman Empire was so great as is sometimes portrayed, one would have expected far better.
EDIT: On a totally different topic, another Roman god was Terminus. Termina would have been the female form, and could have been considered a goddess (and probably was, in prehistory). Terminus was the god of boundary stones (the word also meant boundary stone, as noted in the encyclopedia). It is curious, then, that the Frozen Flame (a "god stone," as it were") was tought by Kid to be in the hands of the Viper Clan, who ruled Termina in CC.