Maslama, of course, did not have such explosive means at his disposal. Katāros’s attempt to ‘give him the keys’ was an invention of mine – albeit one mixed with a grain of truth since the Emperor Justinian II had somehow snuck into the city through the Blachernae sector of the walls when he seized back the throne for the second period of his reign. Although it remains a mystery exactly how. For the Arabs, there was no easy breakthrough and thus Maslama’s host was forced to settle in for a longer siege. The winter that followed was the hardest in memory. The chronicler Theophanes attests that snow settled on the ground for a hundred days – something unheard of at the time – and given the paucity of cover and dwindling food supplies, this made the hardships of the besieging Arab army almost unendurable. All but cut off from the rest of the Umayyad Caliphate, Maslama’s army languished. When Caliph Sulayman also died suddenly that winter, it seemed the prophecy had proved a false hope. Nevertheless, Sulayman’s successor, a younger brother named Umar, was determined not to abandon his half-brother Maslama and his army to their fate. He promised to send a reinforcing fleet in the spring to re-supply Maslama, hoping to tip the balance back in the besiegers’ favour. Alas, he had counted neither on Emperor Leo’s cunning nor his extensive network of spies. According to Theophanes, when the Arab fleet Umar had assembled in Egypt arrived at the Bosporus straits and anchored offshore from Chalcedon, many of their Christian crewmen deserted and crossed the straits in small boats, hailing their emperor with shouts of acclamation. The imperial fire-ships moved in and destroyed most of the Egyptian vessels – still laden with their precious cargo of grain that was so vital to the Arab army’s relief.

It was the Bulgars who delivered the coup de grâce, albeit not quite in the way I described. There was indeed a treaty existing between the Bulgar nation and the empire, agreed between Khan Tervel, his son Kosmeniy, and Leo’s predecessor Theodosios III (whom Leo had deposed). Whether there was any serious doubt that the Bulgars would honour their part of the agreement, it is not recorded. What is known is that Bulgar raids were a continual thorn in the side of Maslama’s besieging army, and these seemed to culminate in a larger action that took place in midsummer of 717, during which the Bulgars routed the beleaguered remains of the Arab army and left twenty thousand of them dead on the field of battle.