 Some hold that in consequence of the principles governing feudal society all medieval churches and their revenues became private property, and that the conflict of Pope Gregory VII and his successors against the Holy Roman Emperors concerning lay investitures was in reality an effort to restore its lost possessions to the ecclesiastical domain.The result of so much strife was the transformation of former proprietary rights into the "Jus patronatus" 'right of patronage'.While ecclesiastical ownership was going through these phases, the canon law decided who must contribute to the maintenance of a particular church, i.e.