[wqaatwt]

Generally battles like Manzikert or similar events were only as disastrous because they were inevitably followed by internal chaos and civil wars.

The free for all nature of the succession meant that whenever the empire was facing major difficulties (i.e. because the emperor was incompetent or due to factors he couldn’t really control) every general or noble within the eyesight of the throne thought that he should have it.

Turkish gains after Manzikert itself were limited and much of the imperial army survived. Of course it marched straight back to Constantinople for its commander to appoint a new emperor (since Romanos IV was captured by the Turks).

Then the Romans kept fighting each other for years while entire Anatolia was gradually lost.

Manzikert was a disaster but they certainly had enough resources to bounce back (i.e. it was certainly not worse than Cannea)

1204 also started as coup attempt by the Venetians to put the son of a former overthrown emperor on the thrown.

[camelCaser]

Exactly! Manzikert was barely a disaster in terms of numbers. Half of Romanos's army was not even on the field. They simply didn't come to his aid, most likely because they were led by a Doukas who wanted one of their own on the throne.

Byzantine history is full of such examples. Civil wars that last decades, never-ending internal strife, and the ever present threat from steppe tribes and caliphates. It's a wonder they survived as long as they did.

[fakedang]

That's precisely what I meant by underlying problems. New emperor? Let's revolt. Emperor captured? Free for all king of the hill. Old emperor returns? Let's blind him, imprison him, and then free for all king of the hill.