At first the rival Popes hurled ecclesiastical thunders at each other; each denounced his rival as Antichrist, and each excommunicated his rival’s adherents. France, Spain, Scotland, the Two Sicilies, acknowledged Clement; Germany, Hungary, and England, and the major part of Italy, recognised Urban.
All the fury of this latter was now turned against Joanna, and he sent a deputation to Hungary to incite Charles of Durazzo to take up arms against her. Charles was not willing to do so. He knew that now Joanna was an old woman, and most unlikely to have children, and that in a few years inevitably the crown would fall to him.
But at this juncture, Joanna made a fatal mistake. Hearing of what the Pope had done, and supposing that Charles would at once comply with his urgency, she declared that she disinherited Charles, and bequeathed all her rights to the Two Sicilies and to Provence to Louis of Anjou, second son of King John of France.
Thereupon Charles hesitated no longer. He raised an army in Hungary, and prepared to invade Neapolitan territories. Pope Urban hired the services of a ruffian captain of a Free Company, Alberic Barbiano, to assist. Urban was not, however, prepared to support Charles without getting some advantage out of him, and he bargained with him that the Principality of Capua should be given to his nephew, Butillo Prignano. When Charles arrived in Rome, Urban decreed the deposition of Joanna, and invested Charles with the sovereignty, and himself crowned him. In the meantime Urban was busy in forming a party in Naples against the Queen, to whom Clement had fled. Among the twenty-six Cardinals whom he created in one day were several Neapolitans of the highest families and dignities in the kingdom. He degraded the Archbishop of Naples, and appointed in his room Bozzato, a man of influence and of powerful connexions in the city. By this means he secured a faction in Naples, opposed to Joanna and to her Pope. The new Archbishop set himself at the head of the opposition. Clement was so alarmed for his safety that he embarked, escaped to Provence, and retreated to Avignon.
The Hungarian and Papal forces marched into the kingdom of Naples, and met with no organised resistance. Joanna was besieged in the Castel Nuovo, and Otho of Brunswick was captured in a sortie. Joanna in vain awaited help from the Duke of Anjou, and was forced by famine to surrender. She was confined in Muro, and at first was well treated, as Charles hoped that she would revoke her will in his favour. But when he saw that she was resolved not to do this, he sent to ask the King of Hungary what was to be done with her. The answer was that the same measure was to be meted out to her that had been measured to Andrew; and she was either strangled whilst at her prayers, or smothered under a feather bed, on May 12th, 1382.