The monarchia Sicula (Sicilian monarchy) was a historical but unduly inflated right exercised from the beginning of the sixteenth century by the secular authorities of Sicily (presently in Italy), according to which they claimed final jurisdiction in Catholic matters, independent of the Holy See.
He gave Roger II the same power "in the sense that if a Papal legate be sent thither, that is a representative of the Pope, you in your zeal shall secure the execution of what the legate is to perform" (ea videlicet ratione, ut si quando illuc ex latere nostro legatus dirigitur, quem profecto vicarium intelligimus, quae ab eo gerenda sunt, per tuam industriam effectui mancipentur).
Despite doubts expressed concerning the authenticity of the document, Ferdinand declared on 22 January 1515: "As for the Kingdom of Sicily, where we exercise the supervision of spiritual as well as of secular affairs, we have made sure that we do so legitimately".
The occasion of the dispute was a question of ecclesiastical immunity, and the differences continued after Count Victor Amadeus II of Sardinia had been made King of Sicily by the Treaty of Utrecht and had been crowned in Palermo in 1713.
The King, through the concession of the Pope, could now appoint the Judex Monarchiae Siculae, who was at the same time to be the delegate of the Holy See and empowered with final jurisdiction of religious matters.
In the bull Suprema of 28 January 1864, which was not published with the prescriptions for its execution until 10 October 1867, Pope Pius IX permanently revoked the monarchia Sicula.