(19 Nov. 461–29 Feb. 468)
Sardinian by birth, son of Crispinus, he was Leo I's archdeacon and one of his legates at the ‘robber council’ of Ephesus (Aug. 449), where he protested against the condemnation of Flavian, bishop of Constantinople (446–9), and with difficulty escaped arrest to bring Leo an eyewitness account of the disorderly proceedings and an appeal from Flavian (now dead). He attributed his escape to John the Evangelist, in whose burial-chamber outside the walls of Ephesus he had hidden himself.
A man of character and energy, Hilarus took his predecessor as his model. All that is known of his dealings with the east is a decretal which he apparently circulated to eastern bishops confirming the councils of Nicaea (325), Ephesus (431), and Chalcedon (451), and Leo's Tome, and also condemning heresies and emphasizing the Roman primacy. If authentic, the object of the decretal was to counter growing monophysite opposition to Chalcedon. Nearer home he struggled to prevent the spread of Arianism in Italy, where it enjoyed the protection of Ricimer, barbarian master of the west till his death in 472. He even had to put up with a second Arian church in Rome, established by Ricimer, and an Arian bishop; but in 467, hearing that the new emperor Anthemius (467–72) might sanction meeting-places for heretics in the city, he boldly confronted him in St Peters and made him swear that he would never consent to such a thing.
Hilarus frequently intervened in Gaul and Spain to consolidate Rome's authority and prevent the breakdown of canonical order. In Gaul he strove, without actually saying so, to rally the bishops around Arles as their metropolis, so that he could use the bishop of Arles as his channel for information and instructions. If he did not succeed in his aim, it was because Leontius of Arles, whom he supported when the rights of his see were violated by Mamertus of Vienne (d. c.475), could not rise to the role expected of him. At a synod held in Sta Maria Maggiore on 19 Nov. 465 (the first Roman synod of which detailed minutes have been preserved) he dealt with complaints brought by Ascanius, metropolitan of Tarragona, against Silvanus of Calahorra, upholding the rights of metropolitans and forbidding bishops to designate their successors. Several of his letters reveal how dependent the Spanish episcopate was on Rome, and how readily and decisively the holy see solved their problems.
Among his buildings at Rome were three chapels attached to the Lateran baptistery, one dedicated to John the Evangelist as a thank-offering for his escape at Ephesus in 449. LP lists his lavish gifts to Roman churches, intended as replacements for the precious metal looted during the Vandal occupation of 455, and records that he founded a monastery at S. Lorenzo fuori le Mura, where he was buried, and a second monastery whose location is unknown. Feast 28 Feb., or 29 Feb. in leap years.
PL 58: 11–31PL Supp 3: 379–81, 441–3JW i. 75–7Thiel i. 126–70LP i, pp. xxxviii, 242–8 (Davis 1: 40–42, 110)Caspar i. 483–95, ii. 10–14DCB iii. 72–4 (J. Barmby)DTC vi. 2385–8 (É. Amann)Levillain ii. 705–7 (C. Sotinel)EThC 54–5 (G. Schwaiger)BSS vii. 737–53 (B. Cignitti)NCE vi. 827 (J. Chapin)Seppelt i. 191–3, 211 f.