After her father's death, she received from the Avignonese Pope Clement VI the official investment of the Kingdom, which was then nominally a vassal of the Papal States.

On June 14, 1345, Clement, after a payment of 44,000 marks, agreed to yield to Andrew the title of king, but only as heir in case of Joan's death.

Joan, who was suspected of having an affair with Louis of Taranto, was at the time under the strong influence of the latter's mother, Catherine of Valois.

Joanna in the meantime had married her cousin Louis of Taranto and had signed a peace with Naples' traditional enemy, the Kingdom of Sicily.

While visiting Aversa, where his brother had been murdered, Louis had Charles of Durazzo assassinated in revenge by his condottiero Malatesta Ungaro and others.

The Neapolitans, who had quickly grown unhappy with the severe Hungarian rule, called back Joan, who paid for her return expedition (including the services of Urslingen's mercenaries) by selling her rights on Avignon to the popes.

Joanna and Louis would leave the Kingdom to await a new trial on Andrew's assassination, to be held in Avignon.

The verdict was Joanna's acquittal from any charge in January 1352, and a peace treaty was signed with Hungary on March 23, 1352.