Alright, so it seems that the majority of crusades were directed at Egypt following the failure of the second to capture Damascus from the Burids. What conditions would be necessary for a conquest of Cairo? Lets' put the timeframe anytime from 1169 (the Byzantine invasion under Manual I) and 1291 (the fall of the final organized Crusader statelet).
My personal favourite scenario would be a more successful Rhomania, dominating the Balkans and Anatolia, invading Egypt alongside their allies the Kingdom of Jerusalem. A Joint Byzantine-Ilkhanid invasion would also be interesting (that is if 1204 does not happen as OTL).
In either scenario I can see the Romans, Crusaders and Mongols squabbling bitterly with one and other over the conquests...However, the query stands: can Mamaluk Egypt be overcome or is this simply one of those "Sealion" moments?
My personal favourite scenario would be a more successful Rhomania, dominating the Balkans and Anatolia, invading Egypt alongside their allies the Kingdom of Jerusalem. A Joint Byzantine-Ilkhanid invasion would also be interesting (that is if 1204 does not happen as OTL).
In either scenario I can see the Romans, Crusaders and Mongols squabbling bitterly with one and other over the conquests...However, the query stands: can Mamaluk Egypt be overcome or is this simply one of those "Sealion" moments?