Attempts to promote reunion between the Churches were made at intervals. The danger from the Mohammedans forced the Emperors of the East to seek help in the West and encouraged the theologians of the West in their maintenance of a perfectly rigid attitude. These approaches began with the forced intercourse of the First Crusade, and in 1098 Urban II held a Council at Bari among the Greeks of Southern Italy, at which Anselm of Canterbury, then in voluntary exile, was put forward to propound the Roman view. In 1112 Peter Grosolanus the defeated candidate for the archbishopric of Milan, as an emissary of Pope Pascal II discussed the points at issue before the Emperor Alexius Comnenus and was answered by Eustratius Archbishop of Nicaea. Again in 1135 Lothair III had sent as ambassador to John Comnenus a Premonstratensian Canon Anselm afterwards Bishop of Havelberg, who held a debate with Nicetas Archbishop of Nicomedia. According to the report which he subsequently drew up at the request of Eugenius III, the points discussed were the procession of the Holy Ghost, the use of unleavened bread and the claims of Rome. A generation later the Emperor Manuel Comnenus held a conference at Constantinople (1170) for the promotion of a union which he sincerely desired; while extant letters of Eugenius III and Hadrian IV to ecclesiastics of the Eastern Church show that the head of the Western Church did not ignore the question of Christian unity. But there were too many political causes of division. The success of the crusaders involved the establishment of the Latin Church in lands claimed by the Eastern Empire. And this affected not only the principalities of Syria, but also Cyprus which Richard Coeur de Lion conquered and handed over to Guy of Lusignan in compensation for his lost kingdom of Jerusalem; as a consequence of which the Greek clergy and monks there were cruelly persecuted. The aggression of the Latin Church was even more conspicuous when the Normans conquered Thessalonica in 1186 and treated the Greek churches and services with contumely, and when Innocent III took advantage of the fact that the Bulgarian monarch had repudiated the suzerainty of Constantinople, to reassert over the Bulgarian Church the supremacy of Rome. The Greeks did not suffer without protest and the massacre of the Latins of Constantinople under the usurper Andronicus (1183) showed the depth as well as the impotence of the Greek hatred. The climax of all previous acts of usurpation was reached in the capture of Constantinople and the organisation of a Latin Church beside the Latin empire. But the Greek Emperors who ruled at Nicaea found it politic to pretend a desire for union of the Churches, and in 1233 and again in 1234 negotiations were carried on between the Greek Patriarch Germanus and some Dominican and Franciscan emissaries of Gregory IX. But the bargaining was one-sided; for while with Rome Christian unity