He said farewell to my grandfather – they clasped one another's arms in the way of kinsmen – and he rode away with his commanders. From on top of the earthen bank outside the palisade I watched the column form up and move on through the Cam valley a short time later, following the Eagle standard.

I never saw Maximus again. And it was to be many, many years before I finally beheld the sword and realized that it had been his sword I had seen that day. That is why Maximus had looked at me the way he did. And that is why he saluted me.

This is where it begins:

First there is a sword, the Sword of Britain. And the sword is Britain.

In the spring of my eleventh year, I travelled with Blaise and Hafgan to Gwynedd and Yr Widdfa, the Region of Snows, in the mountainous north-west. It was a long journey and difficult, but necessary, for Hafgan was going home to die.

He told no one about this, as he found the prospect of leaving his people unspeakably sad. It was the leaving, not the dying he minded; Hafgan had long ago made his peace with Gfod, and knew death to be the narrow door to another, higher life. And, though saying farewell to his kinsmen grieved him deeply, yet he yearned to see again the land of his youth before he died, so the journey became necessary.

Elphin insisted on sending an escort; if he had not done so Avallach surely would have. Given his own way, Hafgan would have forgone this honour; but he relented, since it was not for him that the warriors rode with us.

There were nine in the escort, making a total of twelve in all as we made ready to set out that day not long after Beltane, the fire festival marking the beginning of spring. Hafgan and the escort had come to Ynys Avallach where Blaise and I waited, eager to be off. On the morning of our leaving, I rose early and pulled on my tunic and trousers and ran down to the courtyard to find my mother dressed in riding garb, complete with short cloak and tall riding boots, her hair braided and bound in the white leather thong of the bull ring.

She held the reins of a mist-grey stallion and my first thought was that the horse must be for me. Hafgan stood nearby and they were talking together quietly, waiting for the others to appear. I greeted them and mentioned that I had preferred my black-and-white pony instead.

'Instead? Whatever can you mean?' Charis asked. 'Instead of the stallion, of course.' I pointed out that I was fond of the pony and planned on riding it.

My mother laughed and said, 'You are not the only person ever to master throwing a leg over the back of a horse.'

It was only then that I took in her appearance. 'You would go, too?'

'It is time I saw the place where your father grew up,' she explained, 'and besides, Hafgan has asked me and I can think of nothing I would enjoy more. We have been talking just now of stopping in Dyfed. I would like to see Maelwys and Pendaran again, and I could show you where you were born – would you like that?"

Whether I liked it or not she meant to go, and did. The imagined inconvenience to my notion of playing the warrior never materialized – my mother was more than a match for the rigours of the journey. We did not dawdle or slacken our pace because of her, and, as the familiar landscape sparked her memory with a thousand remembrances of my father, she recalled in vivid detail those first days of their life together. I listened to her and forgot all about pretending to be a fierce battlechief.

We crossed shining Mor Hafren and came to Caer Legionis, Fort of the Legions. The enormous fortress, like so many others in the land, long abandoned and falling into ruin, stood derelict and empty, shunned by the nearby town which still boasted a Magistrate. I had never seen a Roman city before and could find nothing of advantage in its straight streets and houses crowded too close to one another. Aside from the impressive spectacle of a forum and an arena, what I could see of the town inspired little hope for the improvement of life. A city is an unnatural place.

The country beyond was fair to look upon: smooth, lofty hills and winding glens with stone-edged streams and wide flats of grassland ideal for grazing herds of cattle and sheep, and the hardy, sure-footed little horses they bred and sold in horse markets as far away as Londinium and Eboracum.

At Maridunum – where my parents had fled after their marriage, and where I was born – our reception was warm and enthusiastic. King Pendaran considered himself something of a grandfather to both my mother and myself, and was overjoyed to see us. He clasped me heartily by both arms and said, 'I held you, Jad, when you were no bigger than a cabbage.' His fringe of white hair feathered in the wind and he appeared in imminent danger of blowing away. Was this the fearsome Red Sword I had heard about?

Maelwys, his oldest son, ruled in Dyfed, however, and with Pendaran's clucking approval declared a feast upon our arrival and the lords under him, with their retinues, crowded his hall that night.

The lords of the Demetae and Silures were long established in the land and powerful. They had fiercely protected their independence, despite three hundred years of Roman meddling in their affairs – a feat ironically accomplished by forming early and advantageous alliances with the ruling houses of Rome itself, marrying well and wisely, and using their power to keep the Emperor and his minions at a safe distance. Like a rock in the sea, they had allowed the Empire to wash over them; but now that the tide was receding the rock stood unchanged.

Wealthy and proud of their wealth, they lacked any hint of the vanity that so often derives from riches. Simple men, adhering to the ways of their people and resisting change, they had kept alive the true Celtic spirit of their fathers. A few might live in sprawling villas of Roman design, or wear the title of Magistrate; one or another might have comfortably worn the purple, but the eyes that looked upon me in the hall that night saw the world little changed since the day of Bran the Blessed, whom they claimed had settled his tribe in these very hills.

We sat at the high table, my mother and I, surrounded by lords and chieftains, and I began to understand what my people had lost in the Great Conspiracy when the barbarians overran the Wall and attacked settlements as far south as Eboracum, and along both coasts as well. Elphin and the Cymry prospered in the Summerlands, it is true, but were a people cut off from their past – a kind of living death to the Celt. As to that, what had my mother's race lost when Atlantis was destroyed?

After a long and lively meal, Blaise sang and received a gold armband from Maelwys for his song. Then a cry went up for Hafgan to sing. He accepted the harp with diffidence and took his place in the hollow square formed by the tables, strumming the harpstrings idly.

His gaze fell on me and he stopped strumming and beckoned me. I rose and went to him and he placed the harp in my hands and I thought he meant for me to accompany him. 'What will you sing, Chief Bard?' I asked.

'Anything you like, little brother. Whatever you choose will be welcomed in this place.'

Still I thought he meant me to play for him. I fingered a chord and thought. The Birds of Rhiannon? Lieu and Levelys? 'What about the Dream of Arianrhod?' I asked.

He nodded and raised his hand, stepping away to leave me in the centre of the square. Shocked and confused, I stared after him. He merely inclined his head and returned to his place at Maelwys' left hand. What he had done was unprecedented: the Archdruid, Chief Bard of the Island of the Mighty, had relinquished his harp to me, an untried boy.

I had no time to contemplate the implications of his deed – all eyes were on me, the hall hushed. I swallowed hard and marshalled my fleeing thoughts. I could not remember a word of the tale and the pearl-inlaid harp might just as well have been an oxhide shield in my fumbling hands.