II now made serious preparations for the crusade. In the midst of it, however, Pope Honorius III died in Rome on 18 March 1227 without seeing the achievement of his hopes. It was left to his successor, Pope Gregory IX, to insist upon their accomplishment. Besides the liberation of the Holy Land, Honorius III felt bound to forward the repression of Cathar heresy in the south of France, the war for the faith in the Spanish peninsula, the planting of Christianity in the lands along the Baltic Sea, and the maintenance of the unsustainable Latin empire in Constantinople. Of these projects, the rooting out of heresy lay nearest to Honorius III's heart. In the south of France, he carried on Innocent III's work, confirming Simon de Montfort, 5th Earl of Leicester in the possession of the lands of Raymond VI of Toulouse and succeeding, as Innocent III had not, in drawing the royal house of France into the conflict. The most widely important event of this period was the siege and capture of Avignon in 1226. Both Honorius III and King Louis VIII of France turned a deaf ear to Frederick II's assertion of the claims of the Empire to that town. Approval of religious orders and other works Pope Honorius III approved the Dominican Order in 1216, the Franciscan Order in 1223, and the Carmelite Order's Rule of St. Albert of Jerusalem in 1226. In 1219 Honorius III invited Saint Dominic and his companions to take up residence at the ancient Roman basilica of Santa Sabina, which they did by early 1220. Before that time the friars had only a temporary residence in Rome at the convent of San Sisto Vecchio, which Honorius had given to St. Dominic c. 1218, intending it to become a convent for a reformation of nuns in Rome under Dominic's guidance. The studium conventuale at Santa Sabina was the forerunner of the Dominican studium generale at Santa Maria sopra Minerva. In 1217 Honorius III gave the title of King of Serbia to Stefan the First-Crowned. During his pontificate, many of the tertiary orders came into existence. He approved the Franciscan Brothers and Sisters of Penance Rule in 1221 with the bull Memoriale propositi. He also approved the religious congregation "Val des Ecoliers" (Valley of scholars), which had been founded by four pious professors of theology at the University of Paris, France. Being a man