At the beginning of the game I have accidentally sold my golden chalice (not realizing what it was back then).
Is there any way I could get it back? or do I have to visit all merchants to see if I have sold it to them? Or will it be long gone already?
You have to buy it back from the merchant you've sold it. It costs 1500G or something like that.
I noticed that most of the things I sold to vendors remains in their stock, even after 30+ hours of play and traveling to the second area and back. So I think it's pretty safe to say that the vendor you sold the chalice to will still have it in his inventory (you might even be able to pickpocket it if your skill is high enough).
They don't keep everything though, only stuff that you might want to buy back later on. Paintings, cutlery and other "crap" usually disappears after a while.
I'm not 100% sure about this though, it's just something I noticed while playing.
*edit* fixed a typo
