The exhaustion of the combatants in Naples, and the successive deaths of Braccio and Sforza in 1424, freed him from the danger of any intervention from the south. Alfonso abandoned the contest for a time, and Joanna agreed to recognise the claim of Louis of Anjou to be regarded as her successor. Perugia and the other territories of Braccio returned on his death to their allegiance to the Pope. In Rome itself Martin had one source of strength in the support of his own family of Colonna, though their advancement to places of dignity and importance was certain to create difficulties for his successor. Once secure in his temporal dominions, the Pope was free to turn his attention to the general affairs of the Church. The first council which he was bound to summon by the decrees of Constance met at Siena, and was adroitly managed so as to avoid any further limitation of papal authority. By putting himself at the head of the movement to crush the Hussites, and by appointing a papal legate to lead the armies against the heretics, Martin tried to recover for the papacy the position which it had enjoyed in the time of the great crusades of the Middle Ages. But the crusading spirit was dead in Europe, and the successive victories of the Bohemians not only frustrated his designs, but also compelled him to summon a Council to meet at Basel shortly before his own death on February 20, 1431. Eugenius IV., who was unanimously elected to succeed Martin V., had a troubled pontificate of sixteen years. He [Sidenote: Troubles of Eugenius IV.] at once set himself to deprive the Colonna family of the predominance which they had acquired in Rome through the favour of his predecessor; but he could only accomplish this by an alliance with the Orsini, and he thus revived the old feuds among the Roman barons which it was the interest and the duty of the popes to check. Very soon after his accession he engaged in a bitter quarrel with the Council of Basel, and he completely failed in his endeavour to detach Sigismund from the cause of the Council as the price of conferring the imperial crown upon that prince. To make matters worse, he allowed his sympathies with his native city of Venice to involve him in a quarrel with Filippo Maria Visconti of Milan. In 1433 the climax of his misfortunes seemed to be reached, when a combination of Milanese hostility with domestic discontent drove him to fly in disguise from Rome, and to seek refuge in Florence. These accumulated disasters compelled him to adopt a humbler tone towards the Council of Basel, which was conducting negotiations with the Bohemians as if its authority completely superseded that of the Pope.