A history of the Third Fomorian War

The King

Cosmic Mongoose
If you like the setting (Celtic mythology) and like boardgaming I suggest you try and find an old magazine made by SPI in the 80's that was called ARES. In each issue, there was a boardgame on a specific (non historical) theme.
Look for issue #11: Albion, Land of Faerie. The game simulates the 3rd Fomorian War. In that issue you have a game and a complete history of the setting (the departure of King Eberron).
More info on: http://www.boardgamegeek.com/game/3246
and a photo of the map at: http://www.boardgamegeek.com/image/11988
This is where I learnt from Balor's clan.
at http://www.finegames.com/ you can find a copy in mint condition for $32.00.