A strategy/fantasy game played on two decks of standard poker-style playing cards, the basic idea behind The Grass of Parnassus was to create a fun strategy game which could be played on standard cards.
Each player has a city. The objective is to either build your city to a strength of 15 or to pummel your enemy's city to a strength of zero. Each player holds two "decks" of cards - a resource and action deck. Action cards may be played if the player has the corresponding resource cards to spend. Actions include strenghtening your city, hiring a champion to defend your city, deploying spies and thieves, and attacking the enemy city or champion.
Though intended for two players, up to four may play at one time by adding one deck for each additional player; this may add more dimensions to the game as alliances and cooperatives may be formed and broken.
The play is not too intense, though planning a few turns ahead is essential to success.