This paper deals with an object donated by a group of members of the public to the Royal Armoury in Stockholm, Sweden. The donators claimed to own a horse bit that had been used by King Gustav II Adolf's mount in the battle of Lützen, where the King was killed. The bit was a gift to the donators' ancestor, the farmer and politician Petter Jönsson, from the King of Sweden, Oscar I, in the 1850's. In this paper, the donated bit is examined and found unlikely to be the bit used at Lützen. The examination also revealed that the bit now worn by the horse in its display is a prop, included in the group of objects in the 19th century, and that the original bit probably was lost in a fire in 1648.