Kaiphranos
Donor
I disagree. Given how the Caliphate split shortly thereafter, this might have been their one chance to take the city for a long, long time. Those tubes found in an archeological dig about 2 years ago? Might be the secret weapon 'Flamethrowers' dismissed as ASB here. If they had a weapon like that, they might take back all of Anatolia. Maybe, maybe not depending on if the flamethrowers are portable. With time to covert the Bulgars to their heretical faith, they might be able to hold out for decades, maybe centuries, maybe until the discovery of Gunpowder. Which in OTL took until about 700-800 AH. Yesthe Chi'na had it in only about 300 AH, but they didn't use it for anything more than fireworks. It took a long time to use it for actual wars. Have you seen the Walls of the City? You can still see those walls today. 14 feet thick! nothing before gunpowder might breech the wall. Without the Postern gate sneak by those dissatified Romans, how would Allah's armies have gotten in?
A few thoughts:
I think a surviving Roman Empire would actually help the Caliphate's unity, at least for a while--Constantinople still in Roman hands would give them a rallying point, and prevent the overextension into the Balkans that led to the split. And I don't think it will be the Caliphate's only chance to capture the city--the Roman government was fundamentally dysfunctional by that point; breaking the siege of 98 will give them a reprieve, but not much more. Any city will fall eventually, and with Egypt (its traditional breadbasket) in Muslim hands, the city's food situation was pretty untenable. And the naval balance vis-à-vis the Umayyads was not shifting in their favor either--they'd need your super flamethrowers to help them there.
(Does anyone else see the problem with trying to use a flamethrower from a wooden ship, though?)