Annoyed by the queen's opposition, the pope one day angrily said he would shut her up in a convent.

Joan, to avenge the insult, openly favoured Clement VII, the anti-pope, and offered him a home in her own castle, when, pursued by Pope Urban's army, he had taken refuge at Fondi.

But the people rebelled against Clement, and killed the Archbishop of Naples, who had helped to elect him: they broke the cross that was carried in procession before the anti-pope, and hardly allowed him time to make his escape on shipboard to Provence.

Urban declared that Joan was now dethroned, and released her subjects from their oath of fidelity to her, bestowing the crown of Sicily and Jerusalem upon Charles de la Paix, who marched on Naples with 8000 Hungarians.

Joan, who could not believe in such base ingratitude, sent out his wife Margaret to meet her adopted son, though she might have kept her as a hostage, and his two children, Ladislaus and Joan, who became later the second queen of that name.