In The Sims Medieval, there are quite a few quests that you can do to gain experience, money, and resources. Some are much more fun that others, and by default you can only complete a quest once. This cheat will unlock all quests for you, and will even let you do quests as many times as you want.
This will also unlock the Free Play quest that is typically only unlocked once you’ve progressed to a certain point in the game.
To unlock all quests, hit Ctrl+Shift+C on your keyboard to bring up the cheats console. Type in showallquests and hit enter.