LordKalvan said:
Actually, I do believe that the "non-fall" of the Western empire would be likely to result in a stagnant society.
I do realise that this is not the majority view (on this Board at least)
Well, depending on the circumstances of the Western Empire's survival, it could really go both ways. If, say, Theodosius lives for another fifteen to twenty years (which, given that if I recall correctly, he was only in his early fifties at the time of his death - so him making it to early seventies would not have been unheard of at the time), by then the nature of the Empire would have significantly changed due to introduction - and the increased power of - Christianity, but its social institutions would have stayed relatively similar, and thus without a need to innovate, there probably would not have been much of that. Or, maybe if Justinian succeeds in reconquering the West with less difficulty, say, the reconquest of Italy being finished by 540 or so, and no plague that hit afterwards, the continuation from the Roman tradition would make this more like a "traditional" Roman Empire as opposed to the two successor states (Byzantium, which IMO is the evolution of Christian, non-pagan Rome, and HRE, which IMO is less of a true successor state, but still deserves a mention because of its very similar claims). Such an Empire would not be too different in character from the one that was ruled by Constantine - and if it successfully beats off any threats from the outside, there is going to be a lack of impetus to develop both socially and technologically.
On the other hand, if Rome was not the only superpower, that is, Eastern and Western Empires develop very different, separate identities that often clash with each other (which is the eventual premise of a "ATL Dark Ages Map" TL I am writing), there is the standoff that results in participants trying to get an edge, which comes from a variety of sources. Even if the Western Empire survives in a diminished state, the last chance for which IMO save for reconquest from the East would have been during the reign of Majorian, the loss of outlying provinces like North Africa and Gaul, and potential threat from the East could have created a more robust culture and society.
Of course, if we had a Roman Empire that is still in its pre-division borders and at a comparable level of strength, the sheer amount of manpower this empire would be able to muster would be too much for any Islamic eruption to handle, unless there are other factors, like plague, or series of exhausting wars against another power, etc etc. IMO in OTL Islam had a major break because it happened to be in the right place, at the right time... had Mohammad's hajj occurred twenty years after it did in OTL, Islam would have probably ended up as a purely Arabic religion, and would not have gotten to the proportions it did. Without the circumstances turning out "just right", Islam would not have been more than a regional heresy, in terms of the number of believers and their influence on the world at large. A powerful Roman Empire that is not exhausted from wars or other factors would have been too much for it to handle, unless it were to take a similar route to Christianity, that is, finding a champion for the faith that would do same things for Islam as Constantine did for Christianity. Without such a champion, and without outright conquest, in such ATL Islam would not have been able to make it out of Arabia, and possibly east coast of Africa.