Some have suggested that the seal is a forgery. As Avigad noted, the problem is that Manasseh ascended the throne when he was just 12 years old. Would he have had a seal before then? He may have had property of his own despite his young age or the seal could have been used by the custodian of his property. See Avigad, “The Contribution of Hebrew Seals to the Understanding of Israelite Religion and Society,” in Patrick D. Miller et al., eds., Ancient Israelite Religion: Essays in Honor of Frank Moore Cross (Philadelphia: Fortress Press, 1987).