The city of Alexandria had been left…
November 641 CE
The city of Alexandria had been left virtually defenseless following the destruction of the imperial forces at Heliopolis, and it is likely that only a fraction of provincial forces remained garrisoned in the city itself.
Alexandria has historically provided the Empire with a steady income of both money and luxury items, though some scholars speculate that the imposition of especially high taxes in the final decades of imperial rule may have been a considerable factor in causing a sizable amount of the city’s population to defect from Constantinople’s stewardship to side with the Muslim invaders.
Though Constantinople is unable to field an effective force, Alexandria's substantial walls have proved to be valuable assets and were adequate in keeping the Muslim attackers at bay.
After a fourteen month siege, however, imperial officials on November 8, 641, at last capitulate to Amr, turning the city over to Muslim hands.
The impact of such a major event as the loss of Alexandria to Muslim forces is felt throughout the Mediterranean world.
The decrease in the annual grain shipments from Egypt strikes a decisive blow to the imperial economy; besides the simple fact of fewer available resources, the empire has lost untold thousands in taxes from the grain merchants now traveling southward towards Damascus and Alexandria.
The Empire, in such a weakened condition, is barely able to bail itself out financially and in some instances, has to resort to piracy, in some cases attacking merchant ships and “requisitioning” their cargo before distributing it to imperial or allied ports.