HILARUS (Hilarus), POPE, saint. — He was born in Sardinia and was archdeacon of the Roman clergy at the time of St Leo I. In 449, the Pope sent him as legate of the Apostolic See to the so-called "Robber Council of Ephesus." Having rightly sided with Patriarch Flavian, he was forced to leave to escape the wrath of Dioscorus and his partisans. He brought to Rome the appeal that Flavian addressed to St Leo, whose text was discovered in 1882 by A. Amelli in a manuscript of the Chapter Library of Novara and published by him in *S. Leone Magno e l'Oriente* (1882); Th. Mommsen later reproduced the manuscript in *Neues Archiv*, II (1886), pp. 362-64.
Upon becoming pope, he had two oratories built next to the Lateran Baptistery, one of which, dedicated to St John the Evangelist, still exists; on the architrave of the door is an inscription full of gratitude for his liberator: *"Liberatori suo b. Iohanni Evangeliste Hilarus episcopus, famulus Christi."*
His seven-year pontificate (461-68) was not marked by great events. The letters that survive from him relate almost exclusively to southern Gaul. Immediately after his election, I. sent a letter to Leontius, bishop of Arles, to restore the primatial see to that city (*MGH, Epistolae*, III, p. 23, n. 16); however, Leontius does not seem to have been too inclined to become the Pope’s apostolic vicar in France. With an encyclical letter of 3 Dec. 462 to the bishops of southern Gaul, I. ordered the annual provincial synods and gave precepts on the duty of residence and the alienation of ecclesiastical goods. For Spain, where Silvanus of Calahorra had made irregular ordinations, he convened a synod in Rome, held on 19 Nov. 465 in the basilica of St Mary Major, dealing with disciplinary matters and the selection of bishops. The period of peace that Rome enjoyed under I.’s pontificate made possible the enlargement of the Lateran and the restoration of churches damaged by the Vandal sack. He died on 29 Feb. 468, the date on which his feast is observed, though previously it had been celebrated on 10 Sept.