The letter you get at the beginning of the game is promptly shown to Potbello at the inn in New Sorprigal. I got that. This being my first playthrough of the game, I figured that was the end of the letter and I dropped it in town since it was taking up space.

After clearing the castle overlooking the town and the Baa temple COMPLETELY, I checked my quest log to see if a certain someone I found in the catacombs was someone I'd been asked to find. It was then that I noticed I'd need to bring Sulman's Letter (the one I dropped) to Castle Ironfist. Okay, no problem. I'll just go.. pick it.. up... where.. I dropped it...

It's not there.

So do I need to restart the whole game? Also, are items placed inside of containers safe from automatic deletion? That would be helpful to know for future break-proof gaming.

IIRC you can go to the castle Ironfist map and seek out the Oracle (he lives in a starshaped building) there should be a dialogue option something like "lost items or I lost it", this should hand you back your letter with the distinct message of needing to be more careful in the future ;)

The only containers in MM6 I know of that are absolutely safe from automatic deletion are the vaults in the cellar of Goblin Watch. This dungeon is the only place in the game that doesnt respawn, so the chests never reset either :)

In more detail, anything you drop on the ground will be deleted when you leave the map. If you put it in a chest, however, it will stay around until that map resets.

Thanks for the tips, guys. I'll try the oracle later today and see if I can't get the letter back. I'll be more careful about throwing things away. :)

Interestingly enough, the Oracle can be used for certain exploits. Some quests in MM6-8 require you to give a powerful item to the quest-giver. It stinks to lose the item, but you want to complete the quest.

Well, after completing the quest, you can go to the Oracle and tell him, "I lost it." He'll give you the item back. Have your cake and eat it, too. Yay!