So last week I posted about my reading of A Short History of Byzantium by John Julius Norwich as I went about acquainting myself with the history of Byzantium, a subject which I knew things around but not necessarily specifically about. I had reached just before the Fourth Crusade (1204) in which Byzantium was sacked by the Venetians and French Crusaders - and from which Byzantium never recovered.
Upon finishing the book, there are a few more observations about why Byzantium failed.
1) A Loss of Land: After the battle of Manzikert in 1074, Byzantium started to lose land in Asia Minor (now Turkey) which was the heart of its yeoman farmer population. With a loss of population came both a loss of revenue and goods but also a loss of soldiers to enroll in her armies. The loss of wealth meant that the Byzantines were at best at the edge of financial ruin, preserved only by thrifty emperors (which always seemed to be followed by spendthrifts). The loss of population meant Byzantine armies became manned less and less by citizens and more and more by allies and mercenaries.
2) A Loss of Commerce: Byzantine commerce was controlled by the government to a large extent. As times got more difficult in the 1100's and following, the Empire began to sign treaties - with Pisa, Genoa, and Venice - to encourage the trade and goods that it was generating for itself. This trade came at a cost: a surrendering of certain territory and commercial taxation rights. Thus over time, Byzantium could raise taxes on less and less of its goods as they came through commercial partners, thus giving an advantage in profit and price to the Italian city states (and ultimately discouraging its own citizens) and cutting further and further into the taxes it could raise from a dwindling population base.
3) A Loss of Population: By the time of the capture of Constantinople in 1453, the Byzantine Empire could only muster 4983 Greeks and less than 2000 foreigners to defend walls 14 miles long against an army of 100,000. This, in a city that at one time had a population between 500,000 and 800,000 in the 9th and 10th Century. There are references that near the time of the fall, large parts of the city were deserted and the city was really more of a group of smaller towns within a larger, somewhat desolate core.
4) A Loss of Belief: Ultimately, Byzantium fell because there was a loss of belief in the Byzantine Empire. The religious heretics of the Bogomils and the Cathars that fled the Empire found that life under the Turks was not that bad; as time went on, the hatred of the Latins (Rome) had many in the Empire saying "Better the turban than the crown" or "Better submission to the Turks than to the Roman Catholic Church". At that point all was lost: after all, submission to one or the other means that independence has been ruled out.
I would highly recommend the book - if that for no other reason, perhaps more than any other Empire or country of the Middle Ages, Byzantium can speak to 21 Century American in bold and vivid colors.