'Sony?'

'You have from now to the end of September,' he said.

'Good heavens!' I counted quickly on my fingertips. 'It's less than six months.'

'If it were up to me, I would give you as much time as you liked. Unfortunately, we no longer have that luxury.'

'I see now why you called it a challenge.'

I had, I suppose, imagined great deeds of high daring to answer the clarion call I had heard so clearly at the last meeting of the Seven. I had allowed myself to believe that when my turn came to serve, it would involve something far more grand and exciting than stuffing my head full of ancient Greek syntax. To tell the truth, I was slightly deflated.

Pemberton astutely read the disappointment in my mood. 'It is important, Gordon,' he said softly, 'vitally so, or I would not have asked you. What is more, you will learn much to your advantage. That I promise.'

'Quite,' agreed Zaccaria. 'Now then,' he reached into his suit pocket and brought out a calling card, 'I have taken the liberty of giving your name to an acquaintance of mine. His name is Rossides, and he is a scholar of the first order.' He handed me the card. 'He lives in Lothian Street near the university.'

I took the card and read the name aloud. 'M. Rossides, D. Phil.' It was written in both Greek and English. 'Do you think he would be inclined to take on a student of my low aptitude and qualification?'

'Oh, indeed,' Zaccaria assured me seriously. 'He has guided many a floundering Odysseus through the Scylla and Charybdis of aspirated vowels and masculine verb forms. If anyone can get you ready in time, he can.' He reached out and tapped the card in my hand. 'I dare say he'll even get your Latin back in fighting trim.'

'Then I will certainly pay him a visit first chance I get. I'll send him my card and arrange a meeting next week.'

'He is expecting you tomorrow,' Zaccaria informed me. 'Stroke of six. Don't be late. The good professor expects punctuality in his students.'

As if in anticipation of this meeting, the clock in the hallway beyond chimed the hour, and my two guests rose to leave. 'You will want to be getting home, I expect,' said Pemberton. 'Give your lovely Caitlin my best regards, and tell her it might be a good idea to keep the autumn clear in the social diary.' He smiled, enjoying his little mystery. 'I have a feeling you two will be spending some time in sunnier climes.'

I have seen the caliph. All praise to our Great Redeemer, I still live -under sentence of imminent death, it is true – nevertheless, it appears I am to be allowed to draw breath in this world another day. For, after the briefest of audiences, I was returned to my rooms to pray for the salvation of my soul.

Since I have every confidence in my redemption, I will use this time to set down a little more of my tale so that you, dear Gait, will have the benefit. That said, I looked over what I wrote yesterday, and would not change a word.

It was as I said it would be: a little after midday, Wazim came to my room. 'Da'ounk,' he said, bowing low, 'the hour has come. His Majesty the Khalifa Muhammad Ibn al-Hafiz, Protector of the Faithful and Glorious Potentate of Cairo, has commanded you to be brought before him to answer for your crimes.'

This is how they talk.

'Da'ounk' is the closest semblance to my name my little jailer's Saracen tongue could produce. And this word 'hour' is much liked by the Arab tribes, especially Egyptians; it is less easy to designate, but if you quarter the day from sunrise to sunset, and then divide each quarter into three, you will have cut the daylight into twelve equal parts. Each one of these twelve parts is called an hour. There are likewise twelve hours of darkness, too; and all of these have different names, but I do not know them. What is more, Arab philosophers employ various methods of counting these hours throughout the day; and although the reason for this escapes me, it does exercise them greatly.

What Wazim meant, of course, was that my moment of judgement had come. The men with him were dressed in the bold red and yellow of the palace guards-yellow siarcs and trousers, with short red, open-fronted tunics, and large turbans-that is, war helms made of extremely long strips of cloth wound round and round the head in the most cunning fashion imaginable. They carried the distinctive curved sword of the Saracen in the winding cloth that serves the Arab for a belt. They also wielded long, broad-bladed pikes, and curved knives in jewelled sheaths which were fastened to thick gold chains around their necks.

Wazim bowed low as I rose and stepped forwards. I had long ago decided not to argue with my captors, or try to defend my actions in any way, but to accept my portion with good cheer whatever befell me. Since I remained calm and self-possessed, the guards did not lay hand to me, and I was permitted to walk upright and of my own volition into the caliph's presence.

I was taken to a region of the palace I had never visited before. The corridors are wider, the rooms more lavish than any I had seen heretofore, with gold in endless supply gleaming in the furnishings and ornaments, and even the cloth which covered the walls and floors. The rooftrees are polished cedar; the enormous doors are a dark hard wood called ebony, black and shiny as polished jet.

The throne room itself is larger than any banqueting hall known in the West. Wazim told me that once, in observance of the previous caliph's day of birth, fifty men on horseback performed mock battle for the entertainment of scores of spectators. I believe him, for it is an exceedingly spacious hall. And sitting in the centre of it, beneath a live palm tree under which a tent-like canopy had been erected, is the solid gold Throne of Cairo. And on that throne, watching me with eyes as hard as chips of flint, was Hafiz the Resplendent himself.

Surrounded by ranks of servants, aides, scribes, and court officials of various kinds – most of them sitting on the polished marble floor on enormous tufted cushions, the Caliph of Cairo was a much smaller man than I anticipated, very brown, and with the aspect of someone who has spent an active youth beneath the scorching sun of the desert. His skin was deeply creased like well-used leather, and his hair was thick and entirely grey. Like many holy men, his beard was long, and woven into two braids which were drawn up into his turban somehow. And aside from his turban, which was purest white and glistening like sunlight on fresh snow, and bore an enormous blood-red ruby surrounded by the turquoise tips of peacock feathers affixed in gold over his brow, the caliph dressed in the manner of a simple tradesman or farmer. His clothes were spotless and finely made, but of humble, hard-wearing cloth.

He sat on a broad cushion upon his throne with his legs crossed beneath him, as if he were in a tent in a wilderness camp. He frowned when he saw me, and I knew my sentence was sealed.

Still, I bowed low as Wazim presented me and, by way of greeting, I spoke the few words of Arabic which he had taught me. 'Most Excellent and Exalted Khalifa,' I said, 'may the One God who created all men preserve you forever. I am deeply honoured to meet my lord and master, whose kindness and generosity have so long sustained me.'

Although the words were Wazim's, I meant what I said; I was grateful for my benign captivity under his roof. I knew how easily it could have been otherwise.

The great man's frown deepened further, but with consternation. He made no reply, but sat pulling on his long, grey moustache and watching me narrowly.

'As you are an educated man,' he replied in good Latin, 'let us speak directly.'

I was much heartened by this, to be sure; any time an Arab -be he Saracen, Seljuq, Danishman, or Egyptian-deigns to speak to you in your own tongue, number yourself among the few and fortunate. Still, I did not allow my elation to show in my manner or my speech, which would have been disrespectful. 'As you will, lord,' I replied evenly.