The Diocese of Alghero-Bosa () is a Latin Church diocese of the Catholic Church. It is a suffragan of the Metropolitan Archdiocese of Sassari, on Sardinia, insular Italy.

The bishops' seat is Alghero Cathedral. Bosa Cathedral is a co-cathedral of the diocese.

History The town of Alghero was begun by the Doria of Genoa in 1102. In 1106 John, Bishop of Ottana (Othanensis), assisted at the consecration of the Church of the Trinity in Saccargia.Buonaiuti, p. 310, col. 2, derived this claim from Cappelletti, p. 142. The document describing the consecration of Sma Trinità (Codex diplomaticus Sardiniae Vol. 1, p. 193) mentions the bishops present: "Quales fuerunt su donnu de su Archiepiscopu de Turres, su donnu de su archiepiscopu de Oristanis, su donnu de su archiepiscopu de Calaris, misser Albertu episcopu de Sorra, misser Pedru episcopu de Bisarchiu, misser Pedru episcopu de Bosa, su episcopu de Sulcis, su episcopu de Castra , su episcopu de Flumen, su episcopu de Pioaghe, su episcopu de Ortilen, et ateros episcopos, abades, priores, canonigos, preideros, et ateros religiosos...." There is no reference to a Bishop John of Alghero in the document. His inclusion is a conjecture of Cappelletti, derived from Mattei, p. 220, who lists him as the first known bishop of Ottana (Ottanensis, Ortilensis).

After a long period, the see was renewed and confirmed by Pope Julius II in his papal bull "Aequum Reputamus" of 8 December 1503, splitting its territory off from the Metropolitan Archdiocese of Sassari, from the suppressed Roman Catholic Diocese of Bisarcio,F. Amadu, La diocesi mediovale di Bisarcio, (Càller (Cagliari) 1963). Diocese of Castro and Diocese of Ottana.Buonaiuti, p. 310. Codex diplomaticus Ecclesiensis [Historiae Patriae Monumenta, Tomus XVII], (Turin: Bocca 1877), pp. 793-798. Nughes, pp. 19-26. The seat of the bishops of Alghero was to be in Alghero, in the church of the Immaculate Conception, raised to the status of a cathedral. It was granted a Chapter, consisting of three dignities (the Archpriest, the Archdeacon, and the Dean)Martini III, p. 397. and thirteen (later fourteen, then sixteen) canons.Mattei, p. 172. Ritzler & Sefrin, Hierarchia catholica V, p. 78, note 1; VI, p. 76, note 1. Nugues, p. 354.

Bishop Pedro del Frago Garcés (1566–1572) had the cathedral pulled down, in order to replace it with a more commodious building. Funds ran out, however, and it was not until 1589 that Bishop Baccallar took up the building project again.Nugues, p. 355-356.

Pietro Parens, a Genoese, became bishop on 18 December 1503; he was present at the Fifth Lateran Council in 1512.

On 2 April 1549, Bishop Pietro Viguer and the Chapter of the cathedral met and agreed on a set of statutes for the Chapter, which the bishop then published.Nugues, pp. 47-49, with note 164.

In 1582–1583, the plague struck Alghero, with a major loss of life. Dozens of bodies have been discovered in what became the courtyard of the Jesuit college of San Michele in Alghero.Valentina Giuffra, The Plague Cemetery of Alghero, Sardinia (1582-1583): The Bioarchaeological Study (Summertown-Oxford: Archaeopress Publishing Ltd, 2022), passim. I. Budruni, "Pestilenze e ripopolamento ad Alghero nell'età spagnola (1582-1652), Crisi e vitalità di una cultura urbana," in: Quaderni sardi di storia, númber 5, (1985-1986), pp. 109-241 . The college was founded officially on 11 November 1589.Michelle Hobrt (ed.), A Companion to Sardinian History, 500–1500, (Leiden-Boston: E. J. Brill 2017), p. 383. Nugues, p. 361

Bishop Andrés Baccallar (1578–1604) conducted an ad limina visit to Rome in 1590. His report to the Sacred Congregation of the Council survives, and provides detailed information about the state of the diocese of Alghero.Nugues, pp. 353-363. He reported that he had founded (and subsidized) a seminary.Nugues, p. 361: "Seminarium erexi in quo ad presens decem juvenes aluntur, cuius redditus sunt quadringentorum ducatorum ex quibus centum ex redditibus mensae episcopalis assignavi." [I founded a seminary, with presently has ten students, at the cost of 400 ducats, of which 100 come from the episcopal income."] In 1589, he also purchased a house suitable to be an episcopal residence. ALghero had never had an episcopal palace, and the bishops resided elsewhere.Nugues, p. 361: "Palatium episcopale quia a plurimis annis Algherium non agnovit, quod ab eo tempore episcopi non residebant, dirutum penitusque solo aequatum esset, nactus anno superiori praeclaram occasionem cuiusdam palatii quod vendebatur, ad episcoporum commoditatem meis sumptibus emi...."

On 24 May 1727, Pope Benedict XIII granted the king of Sardinia (duke of Savoy), Victor Amadeus II, the privilege of nominating candidates to vacant bishoprics on the island of Sardinia. The privilege was extended to his successors by Pope Pius VI in the bull "Pastoris Officii" of 29 March 1779.Bullarii Romani Continuatio vol. 6 (1848), pp. 86-87.

Synods Bishop Pedro del Frago Garcés (1566–1572) held a diocesan synod on 21–28 May 1572.A. Virdis, "Il II° sinodo algherese del vescovo Frago (1572)," in: Bollettino dell'Archivio Storico Sardo di Sassari vol. XI (1985), pp. 161-253. Nughes, pp. 52-53. Bishop Andrés Bacallar (1578–1604) held a diocesan synod from 9 November to 22 December 1581,Antoni Nughes, El sínode del Bisbe Baccallar: l'Alguer, església i societat al segle XVI, , (Barcelona: Institut d'estudes catalans 1991), pp. 117-153; pp. 227-337 (full text of 1581 synod). and again in 1586.Nughes, p. 155, note 193. Bishop Giovanni Battista Lomellini (1726–1729) Held a diocesan synod in 1728.Constitutiones synodales dioecesis Algariensis et Unionum, (Cagliari: S. Dominici 1728). Bishop Gioacchino Radicati held a diocesan synod on 5–7 December 1785.Prima Synodus diocesana Algariensis ab ... Joachimo Radicati ... Episc. Algarien ... celebrata dieb. V. VI. et VII M. Dec. ... MDCCLXXXV. (Sassari: Typ. J. Piatoli, 1786). J.D. Mansi (ed.), Sacrorum conciliorum nova et amplissima collectio, editio novissima Vol. 38, 1720-1845 (Paris: H. Welter, 1907), p. 985.

On 21 July 1779, the diocese of Alghero lost territory to establish the Diocese of Galtelli-Nuoro.Pope Pius VI, bull "Eam Inter Caeteras", in: Bullarii Romani Continuatio< Vol. 6 (Rome: Apostolic Camera 1843), p. 117, § 6. On 24 September 1798, it gained territory from the Archdiocese of Sassari.Pius VI, bull "Inter Multas tribulationes", in: Bullarii Romani Continuatio, , Vol. 10 (Romae: Apostolic Camera 1845), pp. 162-164, § 4: "Ex quibus quidem quatuor sic dismembratis villis , seu locis tres villas nempe, seu loca de Semestene, Uri et Olmedo dioecesi Algarensi, aliam videlicet de Iteri Fustiarbus erigendæ seu redintegrandæ dioecesi Bisarciensi...." On 9 March 1803 it gained territory from the Diocese of Bosa, and lost territory to establish the Diocese of Bisarcio.Pius VII, bull Divina Disponente, , in: Bullarii Romani Continuatio Vol. 11 (Rome: Apostolica Camera 1846), pp. 463-480, § 5, 18-19. On 31 December 1938 it lost territory to the Diocese of Nuoro.

On 9 September 1919, the collegiate church of Santa Maria ad Nives in the town of CuglieriDecreta authentica Congregationis sacrorum rituum ex actis eiusdem collecta eiusque auctoritate promulgata sub auspiciis SS. Domini Nostri Leonis Papae XIII, Volume 4 (Rome: Typographia polyglotta S.C. de Propaganda Fide, 1900), p. 338. (22km,14mi south of Bosa) was granted the title and privileges of a "minor basilica" by Pope Benedict XV.Acta Apostolicae Sedis Vol. 11 (1919), pp. 409-411.

The Sanctuary of Our Lady of Valverde near Alghero is also notable.John Warr Tyndale, The Island of Sardinia Vol. 1 (London: Richard Bentley 1849), pp. 88-89.

Suppression of diocese of Bosa On 30 September 1986, with the consent of Pope John Paul II, the Congregation of Bishops issued a decree, suppressing the diocese of Bosa and uniting it to Alghero."pro dioecesibus unitis Algarensi et Bosanensi Congregatio pro Episcopis praesenti Decreto plenam earum unionem decernit. The name of the diocese would be Algarensis-Bosanensis. The seat of the new diocese and its cathedral would be in Alghero; the cathedral in Bosa would become a "co-cathedral". The territory of the diocese would be the territory of both dioceses."Nova circumscriptio ecclesiastica in territorio suo includet et comprehendet territoria, quae ad unamquamque dioecesim unitam hodie pertinent." Bishop Giovanni Pes would be the bishop, and was made responsible for implemting the decree.Acta Apostolicae Sedis 79 (1987), pp. 628-631.

Bishops

Bishops of Alghero From 1503 to 1642

Pedro Parente (1503–1514)Parente was appointed bishop of Alghero on 18 December 1503, by Pope Julius II. He died in 1514. Eubel, Hierarchia catholica III, p. 104. Juan Loaysa (1514–1524)Loaysa was a doctor of Canon Law, and a canon of the cathedral of Zamora. He was serving in the papal Curia as Abbreviator of Apostolic Letters. He was appointed bishop on 13 November 1514, and served as Inquisitor of the Holy Office in Sardinia in 1514–1515. In 1516 and 1517 he attended the Fifth Lateran Council. He was transferred to the diocese of Mondoñedo (Spain) on 8 June 1524 by Pope Clement VII. He died in 1525. Eubel III, p. 104 with note 4. Nughes, p. 41. Guillermo Casador (1525–1527)Cas(s)ador had been nuncio to the king of Aragon, and from 1511 was an Auditor of the Rota (judge) in the papal Curia; he was also a Referendary of the Two Signatures. On 19 June 1525, he was appointed bishop of Alghero by Pope Clement VII, and allowed to retain his office of auditor of the Rota. He died on 3 November 1527. Eubel III, p. 104 with note 5. J.Bastida Canal, Guillermo Cassador, (Vic 1961). Nughes, pp. 42, esp. note 139 for the date of death. Bishop-electSolis was appointed by Pope Clement VII before 25 November 1527, on which day the pope wrote to the Chapter of Alghero, which was resisting the appointment of another curial official as bishop; they were threatened with suspension of their ecclesiastical powers. Solis either renounced the bishopric or died before another prelate was appointed on 28 January 1528. Nughes, pp. 42-43. Domenico Pastorello, O.F.M. (1528–1534)On 13 November 1534), Pastorello was named Metropolitan Archbishop of Cagliari (Sardinia, Italy) (13 November 1534 until his death in October 1547) and Bishop of Iglesias (13 November 1534 until his death in October 1547). Eubel, Hierarchia catholica III, p. 104 with note 6. Juan Reina (1534–1538)(3 November 1534 – 5 June 1538), later Bishop of Pamplona (Spain) (5 June 1538 until his death on 18 January 1539) Eubel III, p. 104 with note 7. Durante Duranti (1538–1541)A native of Brescia, Durante had been chamberlain of Pope Paul III. He was named bishop of Alhghero on 25 June 1538. He governed the diocese through a Vicar-general, Giovanni Rocca, and had episcopal functions performed by the bishop of Ampurias. He was consecrated a bishop on 12 March 1540. On 18 February 1541, he was appointed Bishop of Cassano all’Jonio (Italy) (1541–1551), created Cardinal-Priest of Ss. XII Apostoli (9 January 1545). He was Bishop of his native Brescia from 18 February 1551 until his death on 24 December 1557. Eubel III, pp. 29 no. 57; 104 with note 9; 156. Nughes, p. 44. Pedro Vaguer (1541–1566)Vaguer was bishop of Alghero from 4 May 1541 until his death in 1556. He attended the Council of Trent in 1551. Eubel, Hierarchia catholica III, p. 104 with note 11. Nughes, p. 46-50.