"I don't have time to stay in the city for a day, and I think it will be unlikely that you will be able to find much on it, as it is a rather obscure piece of history, somehow managing to thread its way through history almost nu-noticed, leaving only an annotation here, a passing remark there. I can give you a couple of hours, but no more. I have rather pressing business elsewhere. However, assuming that you agree that the pricing on the other items is fair, we might as well exchange goods."
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bluff(1d20+20)[21](unlikely to find anything because it manages to avoid history)
and... the epic fail bluff...
Well, guess no 15 k gold for Tarith... Silly complex skill checks...
Guess i will need to go with plan b after this... persuading him that it is the story behind the item that matters to collectors, not the reality of the item.
Or I can hope for an epic fail sense motive check...
(pricing: 1600 for Tarith alone, 2200 split between Tarith and bishop)