It is true that the monk Arnold of Brescia, burned alive by the Papacy in 1155, fought a long battle (1139-55) against the papal power, creating an immense ferment in Lombardy, and rousing a strong anti-papal movement in Rome itself (Sismondi, _Républiques italiennes_, i, chs. 7, 8; Gibbon, ch. 69); and that, as noted by M'Crie (_Reformation in Italy_, p. 1), "the supremacy claimed by the bishops of Rome was resisted in Italy after it had been submitted to by the most remote churches of the west"; but once papalised, Italy necessarily remained so in her own pecuniary interest. Cp. Rogers, _Economic Interpretation of History_, p. 79. Arnold's movement led even to a revolution in Rome; but after he had ruled there for ten years, overbearing two successive popes, one of greater energy, Adrian IV, excommunicated the city, so expelling Arnold. Adrian then, making a bargain with the emperor Frederick Barbarossa at his coronation, got the republican leader in his power; and the movement ended with Arnold's life. The Papacy was now an irremovable element of division in Italy; and disunion was thenceforth the lot of the land. If we seek to localise the disease, however, we find that no one factor is specially responsible. The alien emperor, coming in from outside, and setting city against city, Pavia against Milan, and nobles against burghers, is clearly a force of strife. Again, whereas the cities might on the whole have combined successfully against the emperor, to the point of abolishing his rule, the Papacy, calling him in to suit its own purposes, and calling in yet other aliens at a pinch, is still more a force of discord. At times the emperors, in the worst days of Roman corruption, had to choose among the competitors nominated to the Papacy by the intrigues of courtesans and nobles and the venal votes of the people, thus identifying the man they chose with their cause. Hildebrandt, again, after securing that the popes should be elected by the cardinals, became the fiercest of autocrats. By his strife with Henry IV he set up civil war through all Italy and Germany; and when in his despair he called in the Normans against Rome, they sold most of the people into slavery.[605] Later, in the minority of Frederick II, Innocent III so strengthened the Church that it was able by sheer slaughter to crush for a generation all Provençal heresy, and was able to prevail against Frederick in its long struggle with him; in so doing, however, deepening to the uttermost the passion of faction in all the cities, and so preparing the worst and bloodiest wars of the future.