True, Londinium considered itself above the petty affairs of Britain. Or, put another way, the concerns of Londinium were the only legitimate concerns of Britain. Flawed as this outlook was, Vortigern ignored it to his peril, and to the ultimate peril of Britain.

Fools! Drowning in their folly. Raving on about Empire and Pax Romana while the tattered remnants of that Empire crumbled around them, and peace became a hollow word. Empty-headed men playing at politics, while the world rushed headlong to its ruin.

Be that as it may, Aurelius had no intention of repeating Vortigern's mistake. He would proceed with the formalities; he would woo the pride-bound citizens of vain-glorious Londinium. In return, he would receive its blessing, and then he could get on with the work of saving the realm.

Sympathy held with Vortigern, but intelligence recognized Aurelius.

So it was that Dafyd, Gwythelyn, Pelleas and I, along with a small escort of monks, came to Londinium. Our trip was speedy and uneventful – which is to say we travelled unmolested through a countryside quickly forgetting terror in its need to gather in the harvest. It was a beautiful harvest time – sun-warmed days and crisp nights. In the morning we awoke to steaming streams and heavy dew; at night we sat before crackling fires with the scent of burning leaves in our nostrils.

Dafyd continued in good health. Though it had been, by Gwythelyn's estimation, a good few years since the bishop had sat a horse, Dafyd gave no indication of discomfort. He rode when we rode and rested when we rested and did not complain. Although I was careful not to overtax him, he seemed wholly unaffected by the journey, remarking often how he enjoyed viewing the wider landscape once more.

We sang, we talked, we discussed and debated – and the distance between Llandaff and Londinium shrank by happy degrees.

It was nearing midday, on a day that had begun overcast with grey clouds of mist that had burned off in time to a bright white haze. Londinium, or Caer Lundein as some now called it, lay squalid before us in its shallow bowl beside the snaking river. A pall of turbid smoke hung grey and drab over the vast expanse, and even from a distance we could smell the fetid reek of the place. Too many people, too many competing desires. My spirit recoiled within me.

There is a church here,' Dafyd reminded me. 'And many good Christians. Where there is great Darkness, the need for the Light is greater also, remember.'

Well, Londinium had need of its church and bishop. Nevertheless, we all took a last deep breath before riding on. At the massive iron gate to the city we were challenged. For •no good reason, it seemed to me. The dolts manning the gate could see we were not Saecsen marauders!

But it is a mark of the arrogance of the place that it deemed all men suspect who were not already within its walls. In the end, we were admitted and allowed to proceed about our business.

The streets were thronged with people and livestock – apparently wandering at will through the city. The din was horrific. Tradesmen hawked their wares in a most unbecoming manner, cattle bawled, dogs barked, beggars chanted, painted women offered themselves for our pleasure. On every hand were men wrangling, shouting, fighting, and contending in any of a thousand different ways in stone-paved streets befouled with garbage and dung.

'If I lived in this place,' remarked Pelleas loudly, 'I should be deaf before winter.'

'If you were not dead first!' Gwythelyn added grimly, speaking my thoughts also.

The place was unspeakable, but possessed of a perverse energy which did not fail to arouse. Londinium was a realm unto itself, and I began to sense something of its deadly allure. Weak men would succumb without struggle to its charms and enchantments; stronger men would be won by the grand and imposing prospect of power. Even wary souls might stumble and fall to their ruin – not for lack of vigilance perhaps, but for lack of fortitude. The Enemy possessed so many wiles and weapons here that all but the most powerful must eventually be overwhelmed in one way or another.

As yet, I saw no evidence of the Light Dafyd proclaimed, and wondered whether he was mistaken after all – even though I know the Light is ever found in the most unlikely places.

Dafyd alone did not seem to mind the stink and noise. He turned a beatific countenance on one and all, passing with the peculiar grace of a saint moving through a shadow-bound world that neither recognizes nor comprehends its true masters.

Perhaps it was myself who did not recognize or comprehend. I admit I have never loved cities – living most of my life, as it happens, close to sun and wind, rock and water, leaf and branch, earth and sky and sea and hill. It was difficult for me to apprehend the subtle expressions of goodness that Dafyd seemed to find. Or maybe I lacked the generosity of forgiveness that he possessed.

We rode directly to the governor's palace – an imposing edifice rising above the tallest rooftops of the city in columned splendour, albeit a splendour now much faded. There we hoped to find Aurelius.

Instead we found a mob.

If the confusion we had thus far encountered was set all on one side, it would not equal the chaos that met us as we rode into the inner courtyard of the palace: a red-tiled square choked with angry men. Many were dressed in an archaic way, affecting Roman garb and appearance. They were calling for the governor to come out into the courtyard to speak to them about some matter, the nature of which we could not discern.

A balcony overlooked the courtyard, and it was to this that the mob addressed itself. But the balcony was empty and the door leading to it remained closed. Aurelius was nowhere to be seen, of course, nor any trace of his army.

'What shall we do, lord?' asked Pelleas. 'I believe there will be a riot here soon. My lord…?'

I heard Pelleas, but I could make no answer. My limbs stiffened as if with sudden and inexplicable cold. The looming violence of the mob held me fast and their cries bound me fast. I could not move or speak, for a powerful awen had seized me.

The bawl of the mob rang in the enclosed courtyard, and their voices became a single voice; a great universal voice sounding a single word: Arthur!… Arthur!… ARTHUR!

I turned my eyes to the sky and saw an enormous purple cloud spreading over the city – it seemed to me an imperial cloak rippling in the wind of an oncoming storm, a cloak much worn and ragged.

When I looked again the people were gone and the courtyard was empty. Dry leaves blew across the weed-grown spaces. The roof of the palace had collapsed and its tiles lay broken and scattered on the ground. The wind whispered in the forsaken places… Arthur… Arthur…

A woman appeared, wearing a long, white garment of the kind highborn ladies are often buried in. Her skin had the pallor of death, and her eyes were sunken and red-rimmed, as if from sickness or mourning.

But she came purposefully towards me over the cracked pavement, the wind whipping her long garment against her legs, blowing her black tresses before her face. She raised her arms to me and I saw she held something in her hands – a magnificent sword, broken now, sundered by a mighty stroke. The ruined weapon dripped blood.

The raven-haired woman approached and held the broken blade to me. 'Save us, Merlin,' she whispered, her voice raw with sorrow. 'Heal us.'

I reached for the sword, but she let it fall from her hands and it clattered on the tiles. I saw in its pommel the Imperial jewel – the eagle-carved amethyst of Magnus Maximus.

The awen passed. I felt a touch on my arm and found that I could move once more. I turned. Pelleas was staring at me, his brow wrinkled in concern. 'Lord Myrddin?'

I passed a hand before my eyes. 'What is it, Pelleas?'