Kulhwch

Well that's the old root of Pendragon, the enchantment of Britain which induces a fantastic technical evolution under the rule of the Good King wearing the Kings' Sword as a spiritual link between the land and the people. That's magic and fantasy, and there are also witches and faeries in this game. But in fact you can easily play it as you want, heavy armors and big stone castles are facultative and appear at a later period of the campaign. You could stick with a more realistic technology with no problem. In fact, medieval knights society can easily be described in more celtic ways. Call your knights free-men, land-owners or champions, and their household shield-carriers, spear-holders, or horse-drivers and you have it. (Sorry I play in French, I have more vocabulary in my own language). Sit your guests in circle at a hall on top of a fortified hill with cauldrons and harpers, rather than have them dine on a table behind heavy hangings on walls, hearing minstrels and jugglers, and you do a lot for the mood. It's how you tell the tale and transmit to the players that's important, Pendragon have plenty of material you just dig in to take what you want. The core mecanism is the passion system and how heroic warriors struggle with to achieve greatness. That's totally "celtic". The only problem is names. But that's a small difficulty compared to the fact that you have a eighty-years campaign to play. That's a unique experience in roleplaying-games.

I'm French from Britanny, and I can't play Pendragon using Anglo-Saxon (English) names for places and people, as it is the language of invader enemy, and a rather big anachronism. I was glad that authors and publishers started to use descriptive names and ancient welsh or latin sources for places and maps in recent books, but I was told on this forum (or was it the other before ?) that it was an unsuccessful experience, as old players were lost. For the sake of coherence of a "modern" and complete Arthurian universe, I think that we should get rid of english names (or use them as reference for precise locations). Medieval sources are vast and contradictory, using fancy or very actual names to please its hearers (of XII-XVth centuries), without the idea of a coherent territory. But KAP sets the game on a map and a time span of 2 or 3 centuries during Great Invasions context. We need proper names in accordance to the purpose of the game. Arthur was a Briton who fought Saxon invasions. Later indeed he pacified the enemy and halted invasions, kept new names in taken over regions, why not. But anglo-saxon folks only conquered Britannia after his death.