Reached by doors from The Mines and the Hall Of Doors. Strange concentric corridors, tapestries, locked doors and four central rooms. An NPC will tell you that you must solve the mystery of the linked vestibule doors to continue further down into the dungeon and another will say that they devised a clever maze of squares to discourage thieves and invaders. An elf cleric says he found nothing in the King's Treasure Room - maybe he missed something - and adds that teleports will speed your way through the dungeon.
Use Read Runes to read the tapestries. One reads 'A hero of strength may open my series of doors' so all you need is sufficient strength to get through. A second says 'A certain lockpick opens my series of doors'. A third says 'A certain key unlocks my series of doors'. These refer, respectively, to Cleowyn's Lockpick and Cleowyn's Key which were found in The Mines. The fourth set of doors can just be opened. The fact is that you can only use one route at any one time. Once one door is opened, all others are impassable. So you need to go through at least four times to reach each central room. It's worth it, though. In one, reached using the Lockpick route, a fight at H10 will gain you the Key to Cleowyn's Palace. In another, the route using Cleowyn's Key, you'll find stairs at G7 to the Palace Corridor, Level 2. The 'strength' route takes you ultimately to a teleport to the King's Domicile, Level 4, from J9. You can win teleport passes round this area, handy for reaching the shop until you have the Teleport spell.