The East–West Schism came about in a context of cultural differences between the Greek-speaking East and the Latin-speaking West and of rivalry between the Churches in Rome, which claimed a primacy not merely of honour but also of authority, and in Constantinople, which claimed parity with that in Rome. The rivalry and lack of comprehension gave rise to controversies, some of which appear already in the acts of the Quinisext Council of 692. At the Council of Florence (1431–1445), these controversies about Western theological elaborations and usages were identified as, chiefly, the insertion of "Filioque" in the Nicene Creed, the use of unleavened bread for the Eucharist, purgatory, and the authority of the Pope. The schism is conventionally dated to 1054, when the Patriarch of Constantinople and the Papal Legate Humbert of Mourmoutiers issued mutual excommunications that have since been revoked. In spite of that event, both Churches continued for many years to maintain friendly relations and seemed to be unaware of any formal or final rupture. However, estrangement continued to grow.