After the fall of Rome, Venice was the doomsday bunker of the elites. Extremely defendable position (back when cannons didn't exist), close enough to the shore to transport things and people quickly, yet far enough that it's impossible to besiege. They pooled all their money to build a city on water while everything else around them was on fire both politically and literally.
Constantinople was literally just a better place to fuck off to than 5th century Venice and was far more safe.
ya venice is just a community on a receding border that labored its way towards impregnability but that took a long time. it wasn't a pre-built bunker by any means and the fortress at the time of late western rome was ravenna
So was Constantinople but which one is called Istanbul now?
Constantinople wasn't a community on a receding border, it was the heart of the empire. And it took centuries for it to fall definitely.
Constantinople is the historical equivalent of a receding hairline
not in the 6th century it wasn't. of course any history that lasts nearly 1000 years is full of ups and downs, and most ideas of extremely long term protracted decline are just wrong. but constantinople's decline starts slowly with the loss of egypt, and then becomes irreversible in 1204. the city was a hollow shell in 1453 and its the ottomans who build it as the center of an imperial administrative state. but if you're a rich roman magnate 800 years earlier and you wanna run away from the lombards, you ain't going to the swamp village close to ravenna.
in the context of the caliphate's eating of Roman territory the idea Constantinople was unsafe actually held a lot of water, with Constans II moving the capital to Syracuse and 10 years after his death the arabs very seriously threatened it in the famous 4 year siege
this is an over-correction of sensationalist narratives from earlier historiography. notions of apocalypse and decline are very present in late roman writing and meshed well with christian eschatology. Gibbon worked mostly with Roman written sources so it really pervaded his work---perhaps to an unreasonable extent---but the notion that things changed imperceptibly is also bunk in light of primary sources spelling that opinion out.
Procopius, Zosimus, Gildas, John Lydus. The Fall of Rome and the End of Civilization is a relatively recent book that consciously catalogues the bad & ugly to synthesize with the current historiography
not the sack of the city of Rome, which was not even the capital at the time (it had been moved to Gaul).
Also Rome itself was sacked by a Roman army led by a Roman general who happened to be of German descent, and IIRC was more an act of opportunistic looting over grievances than it was any sort of invasion.
venice was barely a city when the exarch was punted from ravenna. literally a few villages of Swamp People the romans sent a few titles to the elected leader of--and in those days they were poor and egalitarian, a constantinopolitan noble would've found it positively gauche. also this is 2 centuries after the 'world ended' in Italy, under Justinian's Gothic War & plague
frankly i'd move to Sardinia if peaceful retirement was the idea, that place so steadily faded from roman rule its de facto feudal lords were roman judge offices
