Manawyddan, firstborn of Mighty Llyr, lived long and attained great renown through deeds of courage and valour. He had a kinsman, a man of lesser worth and rank, and this cousin, Medyr, became chafed and annoyed seeing the glory his kinsman enjoyed while he himself had nothing. So up he jumps one shining morning and calls to his tribesmen. 'Lieu knows I am sick of this,' he said. 'All day long I am distressed, but does Manawyddan take notice of my affliction? No, he does not. What shall we do about such a state of affairs?'

The tribesmen looked at one another, but could make no answer. Medyr shook his fist at them. 'Well? I am listening, but hear nothing save the four winds blowing through your heads as through empty shells.'

One of the elder tribesmen spoke up and said, 'Lord Medyr, if it is advice you are wanting, we would be less than good men if we did not tell you to seek out the Black Hag of Annwfn, who knows all that passes everywhere and holds such powers of counsel as to make any man a king who heeds her.'

'At last!' cried Medyr. 'Lieu knows it took you long enough. But this advice seems good to me. I will do as you say.' At once he climbed upon his horse and rode off to seek the Black Hag.

This creature lived in a mound in a birchwood copse near a river. When Medyr found her he summoned her from her dank lair. Foul was her appearance; fouler still the smell which besmote poor Medyr's nostrils. But he had determined to see the thing through and he heeded her advice – which consisted of nothing more than that Medyr should go to Manawyddan and demand to be taken into his care.

This he did. Manawyddan, thinking no ill, received Medyr with good grace and honoured him far above his rank by offering to make him a battlechief and head of a fair warband. Medyr agreed and was satisfied for a little time. But in the end he tired of the work and considered that he might better himself more quickly by raiding. So he rode off and began a life of plunder and pillage, burning holdings, stealing cattle, killing any who made bold to oppose him.

Manawyddan was not the king to stand aside and see his people hurt in this way, so he called forth his best men and asked them to choose from among them the noblest and bravest who should go after Medyr and end his vile slaughter. These were the men who were chosen: Rhonabwy, Kynrig Red Freckles, and Cadwgan the Stout. Everyone agreed that if these men failed it would not be through fault of valour, or courage, wiles, or skill at sword, or through any other fault – for among them they possessed none – but through dark treachery alone.

'Very well,' said Manwyddan when they came before him, 'you know what to do. I bless you and send you on your way. Go in peace and return victorious.'

The three rode out at once and the trail was not difficult to raise, for they simply followed the scorched earth where Medyr had passed. For days and days they rode, and came at last to the holding of Heilyn Long Shanks. As twilight was coming on they decided to stay the night and approached the house.

When they came into the yard they saw an old black cave of a hall with smoke pouring out of it. Inside they saw a floor at once so pitted and bumpy, and so slimy with cow dung and urine, that a man could hardly stand upright without either slipping and falling down or sinking into the stinking mire. And over all was strewn holly branches and nettles which the cattle had been chewing.

Nothing daunted, they continued on and came to a chamber at the end of the hall where they found a sickly hag before a sputtering fire. When the fire guttered the hag threw a handful of chaff into the flames and the resulting belch of smoke brought tears to the eyes. The only other thing that was in this rude chamber was a hair-bare yellow ox-hide. Fortunate indeed was the man who slept on that!

The travellers sat down and asked the hag where the people of the holding were to be found, but she sneered at them, showing her foul teeth. Presently, a thin man, completely bald and withered, entered the hall. He was followed by a grey, stooped woman carrying a bundle of sticks. The woman threw down her bundle before the hag, who made up the fire. The grey woman then began to cook a meal, of which she gave a portion to the three strangers: hard bread and oat gruel and watery milk.

While the three ate this poor fare a fierce rainstorm arose; the wind blew so that trees bent nearly to the ground and the rain fell sideways. Since it was useless to travel on, and since they were tired from their long journey, they decided to stay hi the hall, saying, 'After all, it is only for one night. Fortunate are we indeed if this is the worst thing that befalls us.'

Then they prepared to sleep. And their bed was nothing but a pile of flea-ridden straw with a tattered old greasy cloak thrown over it. Clamping their hands over their noses, they lay down. Rhonabwy's companions fell asleep to the torments of the fleas. But, after thrashing around on the filthy straw, Rhonabwy decided that neither rest nor sleep would come to him if he did not find a more comfortable place. He spied the yellow ox-hide and thought that if he did nothing else he might at least escape the fleas, so he got up and went to lie down on the ox-hide.

No sooner had his head touched the hair-bare old hide than did he fall asleep. At once a vision came to him. And this is what he saw:

He and his friends were riding along beside an oak grove when they heard a tumult the like of which they had never heard before. They halted and, looking fearfully behind them, saw a young man with curly hair and a new-trimmed beard riding a golden horse. This man was green from the hips down to his toes, and he wore a fine yellow mantle that shimmered in the sun. At his side was a golden-hilted sword in a sheath of fine leather, held by a belt with an enormous golden buckle. And the size of the man was all but twice that of any of the three companions!

The three companions knew themselves to be in the presence of a man of power and authority so they waited for him to draw near. 'Peace, friend,' called Rhonabwy as the man approached, and because the man was so big he added, 'and mercy, too.'

The young man in gold and green halted before them. •'You beg peace and mercy from me and you shall have that gladly. Do not be afraid.'

'Our thanks to you, and the thanks of our lord also. Since you grant us mercy, chieftain, tell us your name.'

At this the young man smiled and said, 'I am called Gwyn Ysgawd, and my father is the ruler of this realm.'

'Who might that be?' Rhonabwy asked.

'His name is not uttered except in praise,' Gwyn answered. 'He is Chief Dragon of the Island of the Mighty and its Seven Adjacent Isles, and much else besides, for he is Emperor of the West.'

The three friends peered at one another anxiously. 'We have never heard of this man, great though he undoubtedly is.'

'That surely is a wonder,' said Gwyn. 'But I will allow you to judge for yourselves, for I will take you to him and you can pay him the homage you think he deserves.'

'Fair enough,' said Rhonabwy, and the huge man continued on his way. The three fell in behind him and kept up as best they could. Yet no matter how fast they rode, the yellow horse ahead of them galloped faster. When they breathed in, they seemed to gain a little, but when they breathed out the yellow horse was further away than before.

In this way, they passed over a great plain – wider and more vast than Argyngrog. And they crossed many rivers, each of them wider and more vast than Mor Hafren. And they rode through many forests, each of them wider, darker, and more vast than Celyddon. But at last they came to an immense shore at the very edge of the Island of the Mighty. And spread out along the shore as far as the eye could see in each direction were bright-coloured tents of all sizes – enough to hold the greatest host the world had yet seen.