Within the contracted empire, however, there was no durable progress. Its condensed annals give a picture which even the barbarian West could not outgo. In the period from 668 to 716 seven emperors were dethroned, four of them were put to death, one (while drunk) had his eyes put out, and two more, in addition to two brothers of emperors, had their noses cut off--punishments which in Byzantium became classical. Under Christianity there was certainly more cruelty and demoralization than under early Islam. The Caliph Aboubekr had given to his followers those injunctions: "Be just: the unjust never prosper. Be valiant: die rather than yield. Be merciful: slay neither old men, children, nor women. Destroy neither fruit-trees, grain, nor cattle. Keep your word, even to your enemies." Only those who refused either to become Moslems or to pay tribute were to be slain. In that spirit the Caliph Moawyah rebuilt their Church for the Christians of Edessa. Fifty years later, Justinian II invaded Armenia, and on driving out the Saracens seized and sold as slaves the majority of the Christian inhabitants, reducing the richest parts of the country to desert. And when, after he had been dethroned, deprived of his nose, and exiled for ten years, he returned to triumph over his enemies, the Greek populace applauded him with Biblical quotations as he sat in the circus with his feet on his rivals' necks. The advent of Leo the Isaurian (716) marks an epoch in Byzantine history. Acting as head of the Church, the established function of the eastern emperors, he set himself to check idolatry, first by ordering that the pictures in the churches should be placed high enough to prevent the people from kissing them. On this issue the populace and the lower clergy united against him, to the length of rebellion; and he in turn made his edicts more stringent. Whatever may have been his motives, he acted on principles afterwards founded on by Protestantism; and during a century and a half--save for a relapse from 787 to 813, in which the government was sometimes tyrannically orthodox and sometimes tolerant--his views were more or less fully maintained by succeeding rulers. It is interesting to note that, as repeatedly happened centuries later in the West, a long period of religious strife through the whole State created a party in favour of complete tolerance and liberty of conscience. But though they so far gained ground as to convert the emperor Nicephorus I (802-811), who employed some of them in his ministry, and treated both Paulician heretics and rebels with unusual tolerance, there was no such intellectual life in Byzantium as could long sustain a tolerant policy. It is a miscalculation to suppose, as some do, that the triumph of iconoclasm would have meant the regeneration of the empire. To work regeneration there were needed further forces of variation, since Islam stagnated without image-worship as Byzantium did with it.