Katāros had heard a hundred people say the same in the last week. ‘They won’t break our walls.’ The Byzantines had good cause to be confident. The western fortifications were monumental. Three lines of defence, sheer cliffs of brick and stone. Massive structures that stretched south to the Marmara shore and north to the Golden Horn, sealing the peninsula of Byzantium behind its triple rampart and the brutishly squat towers that strengthened the walls every hundred paces. He looked away to the south. The parapets were lined with hundreds of spearmen, and arrayed among them on the wider walkways were the Byzantines’ own siege machines: mangonels and onagers that stood silent guard over the defences, ready to cast death on any Arab forces foolhardy enough to attempt a direct assault.

The emperor indicated below and to the right where the valley of the Lycus river fell away. The Lycus was the city’s only natural water source, supplying the myriad channels that would eventually erupt from the fountains and bathhouses in the heart of the city. ‘We have to assume that they will cut the water course. Or else divert it.’

‘Let them, Majesty,’ declared Daniel, his tone irritatingly assured. ‘The city is ready. The cisterns are full. The granaries are crammed to bursting. Maslama’s army cannot hurt us.’

‘I hope you’re right.’ Leo scanned with his soldier’s eye further south, distracted perhaps by the sound of chanting. ‘Here they come again.’ He nodded at the small procession of priests approaching from the direction of the Rhesios Gate along the peribolos – the terrace of ground that lay between the inner and outer walls. ‘If the Almighty is persuaded by he who makes most noise, then no one has done more for the city’s defence than those priests.’

Katāros had never quite figured whether Leo was a devout or a cynic when it came to matters of the Faith. Whenever Katāros took him for one, the emperor made a comment that seemed to prove the other. So Katāros reserved judgement and kept his own thoughts on such matters to himself.

Three times they had listened to Patriarch Germanus and his chanting priests pass below, bearing before them the holy icon of the Blessed Virgin in the hope that she would bless the Byzantines’ defences against the coming onslaught. Her special favour on the city was said to be its surest strength. The chronicles recorded how forty years earlier the Mother of God had stood by the Emperor Constantine Augustus in his hour of peril. And despite five years under the heel of the Arab siege, the walls – and the city – still stood. But would the Blessed Mother stand by the Emperor Leo now? If she didn’t, the empire was lost.