Why American school children have never been taught this history is a mystery to me. From William J. Meisler at American Thinker:
In 1453, with the Turks literally on the verge of storming the once-impregnable walls of Constantinople, the Byzantine Greeks persistently devoted their energies to their longstanding passion for arguing over matters of religious minutiae among themselves rather than attending sufficiently to the catastrophe at hand. Even if by that date the final fate of the Byzantine Empire had already been sealed, it is nevertheless marvelous to behold how the Byzantines could not stop themselves from indulging in their customary habits of bitter religious disputation even as the Turk was poised to engulf them forever.
In a similar vein, the political histories of both Ancient Greece and Renaissance Italy are full of examples of factions in a given city regularly allying themselves with the traditional enemies of that city in order to achieve or maintain their own power in their own city.
The dynamic of the whole process of such internal disintegration resulting from intense domestic political rivalry can be said to revolve around a fatal combination of the principles of “divide and conquer” from without and “a house divided against itself cannot stand” from within, with that inevitably present taskmaster the ego blinding the judgment and driving the actions of the ill-fated players involved
