On 9 May 1536, the Emperor Charles V named Cardinal Farnese as the new Archbishop of Monreale in Sicily; his appointment was confirmed on 15 May 1536, by Pope Paul III. But Monreale was not a happy place, since the monks of the Cathedral of Monreale and the clergy of the diocese were in one squabble after another with each other. On 26 July 1549, the Pope was forced to intervene, in a letter in which he referred to the Cardinal under the title of "perpetuus Administrator". A Vicar was appointed for the underage and absentee Archbishop, Msgr. Giovanni Antonio Fassari, titular Bishop of Christopolis in Greece; he was succeeded in 1546 by Pompeo Zambecari. In 1557, he was followed by Msgr. Giovanni Pietro Fortiguerra, Bishop of Cyrene in Libya., The Cardinal allowed the Jesuits to found a college in Monreale, and allowed the priests of the Society to work in the diocese. In 1568, Cardinal Farnese visited his diocese and held a synod. He was accompanied by his librarian, the famous antiquarian and papal biographer, Onofrio Panvinio, who, unhappily, died at Palermo on 16 (?) March 1568. The Cardinal continued to enjoy the income of the diocese until 1573, when he resigned the bishopric.