Flat on my belly, my face so close to the ground I could smell the sedge, I crept forward to peer over the crest of the hill. The first of the enemy was entering the narrow valley from the west. They came on unheeding, a straggling mass, moving in thickened clusters which defined their battlelords. The Irish came first, the Angli after, and slowly. The Picti I did not see, and this caused me to wonder.

'They are so careless,' remarked Gwalcmai, his voice filled with contempt at their stupidity.

'But they are so many,' I reminded him.

He smiled, his teeth showing white in the gloom. 'The more glory for us, friend Bedwyr.'

'Listen!'

The blast of a horn echoed in the glen. It was Rhys, with Arthur's hunting horn – the signal to attack. And suddenly there he was, springing up out of the river mist and hurtling into the startled barbarians. All along the river men rose as one. Their shout carried to the hilltops and echoed along the glen.

The barbarian host was thrown into confusion at once. Those leading were forced back into the mass behind. The Britons thrust ahead, following Arthur at a run. He had taken a white horse, so that he could be more easily seen in the murk, and he flew at the enemy like a harrying hawk.

The sight of him driving fearlessly into the churning wall of foemen made Gwalcmai gasp. 'Is he always so daring?' he asked in astonishment.

'It is his way.'

'I have never seen the like of it. Who can match him?'

I laughed. 'No one. He is a bear in battle – a great mad bear. No one matches him for strength or valour.'

Gwalcmai shook his head. 'We heard he was a stout battlechief, but this… ' he fell silent for want of words.

'Beware,' I warned, 'he expects no less of the men who follow him.'

7 will follow him if he will have me,' Gwalcmai vowed solemnly.

I clapped the prince on his shoulder with a gloved hand. 'Well, you are indeed a fortunate man, Gwalcmai ap Lot. For today you have the happy chance to prove yourself worthy.'

So saying, I rose and drew on my war helm. I walked back to the picket, mounted my horse and took up my long spear, then gave the signal to the others who were already mounted and waiting. We advanced to the crest of the hill and poised there, ready to sweep down into the fray.

We did not wait long, for the first ranks of Angli had already seen what Arthur was about and were running up the side of the hill to evade the chaos choking the centre of the glen, hoping to surround the Cymry. As yet, no one had crossed the river to come at him from the other side.

I raised my spear to heaven. 'For God and Britain!' I cried, and my cry was answered in kind. And then I was racing down the hillside, my cloak rippling out behind me, the wind singing from my dark-glinting spearhead.

So heedless were the Angli that they did not see us until we were right on top of them. The first ranks of warriors went down before us like wheat ripe to the scythe. The speed and force of our charge carried us well into their quickly scattering swarm.

We reformed the line and galloped up the hillside, turned, and came sweeping down upon them again. The Angli saw what we intended and fled before us, running, stumbling, rolling, picking themselves up and running again. We drove them before us like so many sheep for the slaughter.

They did not even try to fight.

I reined up and gathered the horsemen to me. 'Let them go! Let them go! We ride now to support Arthur!' I pointed with my spear down the hillside where the main force laboured. The Irish, by dint of numbers alone, had succeeded hi halting Arthur's advance. By cutting in from the side, we could divide the Irish force and keep the Angli penned behind, where they could do nothing.

Oh, Arthur had chosen the battle place well. The land worked for us and against the enemy; their greater numbers were no use to them now.

Setting my spear, I wheeled my horse and charged. I heard a wild war whoop beside me and Gwalcmai galloped past, his face alight with the battle glow. I lashed my horse to match his pace and the ground trembled beneath us. The beat of our steeds' pounding hooves sounded like a throbbing drum.

Down and down we came, plummeting like eagles, swifter than the wind. The terrified Irish heard the terrible din of our coming and threw their round shields before them – as if this could stop the thunder breaking over their heads.

The clash of our meeting sounded like a thousand anvils being struck at once. Steel flashed. Men screamed. The air shuddered with the shock. I thrust with my spear again and again, opening a wide path before me.

Gwalcmai rode at my right hand, matching me thrust for thrust. Together we drove straight into the heart of the battle, where Arthur's white horse reared and plunged. Any who came before us fell – either to our spears or to the swift and deadly hooves of our battle-trained horses.

I will tell you how it is to fight on horseback, shall I?

You feel the enormous surge of power beneath you and the rhythmic roll of the beast's flanks as its legs stretch and gather. The strength of the great creature becomes your strength, rising through you and through the shaft of the spear in your hand. With the enormous weight of the animal behind it, that hardened length of ashwood becomes indestructible; the flared iron leaf of the spear head penetrates anything: wood, leather, bone.

As you begin the charge, the enemy appears as massive and faceless as a wall. As you close, the wall begins to splinter and fall inward upon itself. Then you see individual timbers – men – as they collapse before you. There is a terrible instant when you see their eyes bulge and mouths gape as they go down. And then they are gone and you are free.

The shock of the clash washes over you like a sea wave, swelling, cresting, rolling, and moving on. The sound of the battle is a roar in your ears and a blur before your eyes. You see the glint of metal. You see the point of your spear like a point of light, like a Beltane firebrand, as it thrusts and thrusts.

You smell the thick, salty sweetness of blood.

You are at once greater and more powerful than you can imagine. You expand to fill the whole of this worlds-realm. You are formidable. You are invincible. You are God's own idea of a warrior and his hand is beneath you, upholding you. His peace flows from your heart as from a wellspring.

All these things and more I knew as I hurtled like a flaming star to Arthur's side. The Irish fell before me and many did not rise again.

'Arthur!' I cried, scattering the last of the foe before me as I fought to his side.

'Good work!' he shouted. The press of battle was thicker here and the spear was no help. Arthur's sword was in his hand and I saw his arm rising and falling in deadly rhythm. I shoved my spear into its holder beneath my leg and drew my sword, unslinging my shield at the same time. Then I settled into the grim business at hand.

All around us the Cymry hacked at the foe, who fell back and back before us. They were giving ground and that was good. Oh, but it was slow going. We pushed on, and it was like wading to shore against an putrushing tide.

And then, all at once, the tide changed and we found ourselves being pulled along with it. I looked out across the glen to see what the cause might be and I saw Idris and Maglos sweeping down the hillside to meet an Angli counter-attack from the other side of the river. The attack was crushed before it could begin.

Seeing their hope extinguished so quickly and efficiently, the Irish abandoned the fight.

'They are retreating!' shouted Arthur. 'Follow me!' He raised his sword and his war cry was lost in the shouts of retreating Irish. I saw his white horse leap ahead and we gave chase.

We pursued them all the way back to the ford at the Glein. Here the valley widened and flattened, and here the Angli chose to halt their retreat and give battle once more.