GREGORIO IV, POPE. — A Roman nobleman, priest of the titulus of S. Marco, elected pope without the intervention of the emperor Ludovico il Pio, but consecrated only after the arrival of an imperial legate who examined the election according to the Constitutum of 824; he was pope from 827 to 844. In the revolts of the sons of Ludovico il Pio against their father, G. IV unfortunately supported Lotario, the eldest son. Before crossing the Alps, he sent Agobardo, archbishop of Lione, a letter in which he prescribed prayers and fasts to bring down divine blessing upon the undertaking he was contemplating. In a formal invitation to the bishops to come and meet him, G. declared his peaceful intentions, namely, to restore concord between the father and his sons. While Agobardo supported the Pope, condemning the attacks on the division of the Empire of 817, the imperialist bishops protested, in a very forceful collective letter, against G.’s conduct in the aforementioned matter. G. IV’s polemical reply did not increase his authority, already compromised by the inglorious adventure. Pascasio Radberto and Wala, who had hastened to the Pontiff, vainly sought to suggest arguments to him to justify his action.
Upon returning from the “field of lies,” he found a new danger in Italy: the Arabs of North Africa, who had landed in Sicily in 827 and had been masters of Palermo since 831. The Moors of Spain, too, grew so bold as to land on Italy’s Tyrrhenian coasts. To defend the mouth of the Tiber, G. IV had the fortifications of Ostia rebuilt (840–41), and named it Gregoriopoli after himself. Moreover, G. IV had also shown himself in Rome to be a diligent restorer of religious and civic buildings.
In 831–32 G. IV confirmed Ansgario, the “apostle of the north,” as archbishop of Amburgo and appointed him papal legate for the Danes, Swedes, and northern Slavs. In the affair of Ebbone, archbishop of Reims, G. IV was in no hurry whatsoever to sanction the sentence of deposition pronounced at Thionville in 835. G. IV died in January 844 after a pontificate of seventeen years.