Italians were in a state of ferment and of radical transformation when the first signs of a revival of the communes appeared. Neither the barbarian rule nor the Empire had ever really mastered the social order of the peninsula; and exactly when feudalism was first founded and seemed likely to spread everywhere and assure the quiet supremacy of the emperors over Italy, fresh causes of peril and strife suddenly sprang into existence. Papacy and clergy attained to loftier and more menacing power; the immunities lavished on prelates, from dread of the laity, rendered them temporal potentates dependent on the emperors, while as spiritual dignitaries they owed obedience to the Pope: thus practically enjoying a double investiture. This led to much disorder and scandalous corruption in the Church, since prelates were converted into feudal lords, holding sway over cities, making war on other territories, keeping open court, and indulging in every worldly pleasure. The Popes wished to re-establish discipline, to maintain absolute rule over the bishops, and nominate them unhindered; but this was opposed by the emperor, since the temporal authority of the prelates made them logically subject to his rule as well. Thus began the famous war of investitures between the Papacy and the Empire, the issue of which was so long undecided. Meanwhile neither the Church, the Empire, nor the feudal system could obtain complete mastery over the social movement, and the confusion was increased by their continual disputes. This state of things weakened even the authority of the prelates; and then the communes, having necessarily learnt the art of self-government during the period when dioceses were left vacant, having noted the prosperity of the Southern republics, and found their strength increased by the extension of commerce and the feudal disorganisation, finally saw that the moment to achieve freedom had arrived. Even in cities ruled by lay nobles, things followed the same course, since to side either with the Empire or the Church always served to excite much enmity against those in power, and procured many allies for the weaker party.