An artifact most Giovanni would give somebody's soul for, the True Vessel is a small earthenware jar, holding maybe a pint of vitae. The jar is sealed with beeswax and a curse and cannot be opened by any force known to anyone currently familiar with it.
The matter was brought to the Giovanni's attention by the Capuchin. It is believed to hold a small amount of Cappadocius' blood and soul sealed by Japheth and Constancia, which Augustus Giovanni is desperate to obtain. The True Vessel was rumored to have been hidden in the library of Erciyes but was lost when Claudius Giovanni ordered the burning of the temple-fortress.