A coin is found in the alcove next to the shrine, which can be given to Messalina, next to Dr. West.
Messalina trades you a rare book for the coin, which can be traded to Bernard.
Bernard will trade you an amphora of wine, which can be given to Bedwyr, the enchanter of the Phoenix Inn.
Bedwyr gives you an imp limb, which may then be given to Dr. West.
Dr. West will then pay you for it with a miniature zeppelin, which is given to Casca, who is across the street.
Casca will give you a compass, which can be given to Virginius, a guard in the marketplace near the central statue.
Virginius will give you a pearl necklace, which can be given to Flora, the female guard in the Phoenix Inn.
Flora will then give you a rare raccoon rune, which can finally be given to Valeri, who is studying the glowing Maxos runes.