During the 15th and 16th centuries, the Catholic Church celebrated more general councils than during any similar period in its history. The Council of Pisa I, 1409 attempted to end the Great Western Schism but instead succeeded in adding a third pope. To bolster his position, the Pisan pope called a council that met in Rome, 1412–1413. The Council of Konstanz, 1414–1418 healed the schism but introduced new issues by declaring the superiority of a council over all Christians and requiring the celebration of councils on a regular basis. In accord with that requirement, a council was held at Pavia-Siena, 1423–1424, with another later at Basel-Lausanne, 1431–1449. The pope tried to transfer the latter council to Ferrara (1437), but the majority of the fathers remained at Basel. The Council of Ferrara (1438–1439) moved to Florence (1439), where it issued decrees uniting the Eastern and Latin churches and condemning the council still being held at Basel. The papal council ended in Rome (1445). In their conflict with Julius II, some cardinals and rulers called a council that met at Pisa (1511) but then transferred to Milan, Asti, and Lyons (1511–1512). To combat that council, Julius II called his own council to meet in the Lateran Basilica in Rome (Lateran V, 1512–1517). These eight councils dealt with themes of church unity (healing schisms), ultimate authority (pope or council), doctrinal issues (the teachings of Wyclif, Hus, Falkenberg, Grabon, and Favaroni; Filioque, Eucharist, Purgatory; immortality of the soul, montes pietatis; etc.), Crusades (attempts to fend off the Turks), and reform (of morals, pastoral care, preaching, education of clergy, the privileges of religious orders, etc.). Scholars have debated the legitimacy of various councils and the origins, meaning, reception, and implementation of their decrees.