The campaign against images as part of a general reformation of the Church and State. Leo III's idea was to purify the Church, centralize it as much as possible under the Patriarch of Constantinople, and thereby strengthen and centralize the State of the empire. There was also a strong rationalistic tendency among the Iconoclast emperors, a reaction against the forms of Byzantine piety that became more pronounced each century. This rationalism helps to explain their hatred of monks. Once persuaded, Leo began to enforce his idea ruthlessly. Constantine of Nacolia came to the capital in the early part of his reign; at the same time John of Synnada wrote to the patriarch Germanus I, warning him that Constantine had made a disturbance among the other bishops of the province by preaching against the use of holy pictures. Germanus, the first of the heroes of the image-worshippers, then wrote a defence of the practice of the Church addressed to another Iconoclast, Thomas of Claudiopolis. But Constantine and Thomas had the emperor on their side. In 726 Leo III published an edict declaring images to be idols, forbidden by Exodus 20:4-5, and commanding all such images in churches to be destroyed. At once the soldiers began to carry out his orders, whereby disturbances were provoked throughout the empire. There was a famous picture of Christ, called Christos Antiphonetes, over the gate of the palace at Constantinople. The destruction of this picture provoked a serious riot among the people. Germanus, the patriarch, protested against the edict and appealed to the pope. But the emperor deposed him as a traitor and had Anastasius, formerly syncellus of the patriarchal Court, and a willing instrument of the Government, appointed in his place. The most steadfast opponents of the Iconoclasts throughout this story were the monks. It is true that there were some who took the side of the emperor but as a body Eastern monasticism was steadfastly loyal to the old custom of the Church. Leo therefore joined with his Iconoclasm a fierce persecution of monasteries and eventually tried to suppress monasticism altogether.
The pope at that time was Gregory II. Even before he had received the appeal of Germanus a letter came from the emperor commanding him to accept the edict, destroy images at Rome, and summon a general council to forbid their use. Gregory answered, in 727, by a long defence of the pictures. He explains the difference between them and idols, with some surprise that Leo does not already understand it. He describes the lawful use of, and reverence paid to, pictures by Christians. He blames the emperor's interference in ecclesiastical matters and his persecution of image-worshippers. A council is not wanted; all Leo has to do is to stop disturbing the peace of the Church. As for Leo's threat that he will come to Rome, break the statue of St. Peter, and take the pope prisoner, Gregory answers it by pointing out that he can easily escape into the Campagna, and reminding the emperor how futile and now abhorrent to all Christians was Constans's persecution of Martin I. He also says that all people in the West detest the emperor's action and will never consent to destroy their images at his command. The emperor answered, continuing his argument by saying that no general council had yet said a word in favour of images that he himself is emperor and priest in one and therefore has the right to make decrees about such matters. Gregory writes back regretting that Leo does not yet see the error of his ways. As for the former general Councils, they did not pretend to discuss every point of the faith; it was unnecessary in those days to defend what no one attacked. The title Emperor and Priest had been conceded as a compliment to some sovereigns because of their zeal in defending the very faith that Leo now attacked. The pope declares himself determined to withstand the emperor's tyranny at any cost, though he has no defence but to pray that Christ will send a demon to torture the emperor's body that his soul be saved, according to 1 Corinthians 5:5.
Meanwhile the persecution raged in the East. Monasteries were destroyed, monks put to death, tortured, or banished. The Iconoclasts began to apply their principle to relics also, to break open shrines and burn the bodies of saints buried in churches. Some of them rejected all intercession of saints. These and other points, though not necessarily involved in the original programme are from this time generally added to Iconoclasm. Meanwhile, St. John Damascene, safe from the emperor's anger under the rule of the Khalifa was writing at the monastery of St Saba his famous apologies against those who destroy the holy icons. In the West, at Rome, Ravenna, and Naples, the people rose against the emperor's law. This anti-imperial movement is one of the factors of the breach between Italy and the old empire, the independence of the papacy, and the beginning of the Papal States. Gregory II already refused to send taxes to Constantinople and himself appointed the imperial dux in the Ducatus Romanus. From this time the pope becomes practically sovereign of the Ducatus. The emperor's anger against image-worshippers was strengthened by a revolt that broke out about this time in Hellas, ostensibly in favour of the icons. A certain Cosmas was set up as emperor by the rebels. The insurrection was soon crushed, and Cosmas was beheaded. After this a new and severer edict against images was published, and the fury of the persecution was redoubled.
Pope Gregory II died in 731. He was succeeded at once by Gregory III, who carried on the defence of holy images in exactly the spirit of his predecessor. The new pope sent a priest, George, with letters against Iconoclasm to Constantinople. But George when he arrived, was afraid to present them, and came back without having accomplished his mission. He was sent a second time on the same errand, but was arrested and imprisoned in Sicily by the imperial governor. The emperor now proceeded with his policy of enlarging and strengthening his own patriarchate at Constantinople. He conceived the idea of making it as great as all the empire over which he still actually ruled. Isauria, Leo's birthplace, was taken from Antioch by an imperial edict and added to the Byzantine patriarchate, increasing it by the Metropolis, Seleucia, and about twenty other sees. Leo further pretended to withdraw Illyricum from the Roman patriarchate and to add it to that of Constantinople, and confiscated all the property of the Roman See on which he could lay his hands, in Sicily and Southern Italy. This naturally increased the enmity between Eastern and Western Christendom. In 731 Gregory III held a synod of ninety-three bishops at St. Peter's in which all persons who broke, defiled, or took images of Christ, of His Mother, the Apostles or other saints were declared excommunicate. Another legate, Constantine, was sent with a copy of the decree and of its application to the emperor, but was again arrested and imprisoned in Sicily. Leo then sent a fleet to Italy to punish the pope; but it was wrecked and dispersed by a storm. Meanwhile every kind of calamity afflicted the empire; earthquakes, pestilence, and famine devastated the provinces while the Moslems continued their victorious career and conquered further territory.
Leo III died in June 741, in the midst of these troubles, without having changed policy. His work was carried on by his son Constantine V, who became an even greater persecutor of image-worshippers than had been his father. As soon as Leo III was dead, Artabasdus seized the opportunity and took advantage of the unpopularity of the Iconoclast Government to raise a rebellion. Declaring himself the protector of the holy icons he took possession of the capital, had himself crowned emperor by the pliant patriarch Anastasius and immediately restored the images. Anastasius, who had been intruded in the place of Germanus as the Iconoclast candidate, now veered round in the usual Byzantine way, helped the restoration of the images and excommunicated Constantine V as a heretic and denier of Christ. But Constantine marched on the city, took it, blinded Artabasdus and began a furious revenge on all rebels and image-worshippers. His treatment of Anastasius is a typical example of the way these later emperors behaved towards the patriarchs through whom they tried to govern the Church. Anastasius was flogged in public, blinded, driven shamefully through the streets, made to return to his Iconoclasm and finally reinstated as patriarch. The wretched man lived on till 754. The pictures restored by Artabasdus were again removed. In 754 Constantine, taking up his father's original idea summoned a great synod at Constantinople that was to count as the Seventh General Council. About 340 bishops attended; as the See of Constantinople was vacant by the death of Anastasius, Theodosius of Ephesus and Pastilias of Perge presided. Rome, Alexandria, Antioch, and Jerusalem refused to send legates, since it was clear that the bishops were summoned merely to carry out the emperor's commands. The event showed that the patriarchs had judged rightly. The bishops at the synod servilely agreed to all Constantine's demands. They decreed that images of Christ are either Monophysite or Nestorian, for since it is impossible to represent His Divinity they either confound or divorce His two natures. The only lawful representation of Christ is the Holy Eucharist. Images of saints are equally to be abhorred; it is blasphemous to represent by dead wood or stone those who live with God. All images are an invention of the pagans; are in fact idols, as shown by Ex 20:4-5; Deut 5:8; John IV:24; Rom I:23-25. Certain texts of the Fathers are also quoted in support of Iconoclasm. Image-worshippers are idolaters, adorers of wood and stone; the Emperors Leo and Constantine are lights of the Orthodox faith, our saviours from idolatry. A special curse is pronounced against three chief defenders of images: Germanus, the former Patriarch of Constantinople, John Damascene, and a monk, George of Cyprus. The synod declares that the Trinity has destroyed these three.
The bishops finally elected a successor to the vacant see of Constantinople, Constantine, bishop of Sylaeum, who was of course a creature of the Government, prepared to carry on its campaign. The decrees were published in the Forum on 27 August 754. After this the destruction of pictures went on with renewed zeal. All the bishops of the empire were required to sign the Acts of the synod and to swear to do away with icons in their dioceses. The Paulicians were now treated well, while image-worshippers and monks were fiercely persecuted. Instead of paintings of saints the churches were decorated with pictures of flowers, fruit, and birds, so that the people said that they looked like grocery stores and bird shops. A monk Peter was scourged to death on 7 June 761; the Abbot of Monagria, John, who refused to trample on an icon, was tied up in a sack and thrown into the sea on 7 June 761; in 767 Andrew, a Cretan monk, was flogged and lacerated till he died; in November of the same year a great number of monks were tortured to death in various ways. The emperor tried to abolish monasticism; monasteries were turned into barracks; the monastic habit was forbidden; the patriarch Constantine II was made to swear in the ambo of his church that although formerly a monk, he had now joined the secular clergy. Relics were dug up and thrown into the sea, the invocation of saints forbidden. In 766 the emperor fell foul of his patriarch, had him scourged and beheaded and replaced by Nicetas I, who was, naturally also an obedient servant of the Iconoclast Government. Meanwhile the countries which the emperors power did not reach kept the old custom and broke communion with the Iconoclast Patriarch of Constantinople and his bishops. Cosmas of Alexandria, Theodore of Antioch, and Theodore of Jerusalem were all defenders of the holy icons in communion with Rome. The Emperor Constantine V died in 775. His son Leo IV, although he did not repeal the Iconoclast law was much milder in enforcing them. He allowed the exiled monks to come back, tolerated at least the intercession of saints and tried to reconcile all parties. When the patriarch Nicetas I died in 780 he was succeeded by Paul IV, a Cypriote monk who carried on a half-hearted Iconoclast policy only through fear of the Government. But Leo IV's wife Irene was a steadfast image-worshipper. Even during her husband's life she concealed holy icons in her rooms. At the end of his reign Leo had a burst of fiercer Iconoclasm. He punished the courtiers who had replaced images in their apartments and was about to banish the empress when he died 8 September 780. At once a complete reaction set in.