The Diocese of Porto–Santa Rufina is a Latin suburbicarian diocese of the Diocese of Rome and a diocese of the Catholic Church in Italy. It was formed from the union of two dioceses. The diocese of Santa Rufina was also formerly known as Silva Candida.

From 1967, the diocese has had both a titular cardinal bishop, and a resident bishop who handles the diocesan business.

Porto was in ancient times Portus, the chief harbour of Rome. It owes its origin to the port built by Claudius on the right of the Tiber, opposite Ostia. Trajan enlarged the basin, and in a short time there grew around it a city which eventually became independent of Ostia. Porto became a separate city in the 4th century. Between 337 and 341, a statue was erected by the ordo et populus civitatis Flaviae Constantinianae Portuensis.

It was near Porto that Julius Nepos compelled Emperor Glycerius to abdicate (474). During the Gothic War the town served the Goths (537 and 549) and the Byzantines (546–552) as a base of operations against Rome. In the 9th and 10th centuries it was sacked on several occasions by the Saracens. In 849 Pope Leo IV fortified it and established there a colony of Corsicans for the defence of the coast and the neighbouring territory, but the city continued to decay.

Christianity was early established there. Several martyrs of Porto are known, including Herculanus, Hyacinthus, Martialis, Saturninus Epictetus, Maprilis and Felix. The place was also famous as the probable see of St. Hippolytus (1st half on third century).

In 314 Gregorius was bishop. The great xenodochium, or hospice, of Pammachius was built about 398.

In 682, it is recorded that Pope Leo II was consecrated by the bishops of Ostia, Porto and Velletri (the See of Albano being vacant). The bishop of Porto was one of the seven (then six, when Porto was combined with Santa Rufina) episcopi hebdomadarii, who presided at the high altar of the Lateran Basilica in rotation during the weekdays; the system is first mentioned at the time of Pope Stephen III (768–772), though it was certainly much older.

On 1 August 1018, Pope Benedict VIII confirmed for Bishop Benedictus all the possessions of the church of Porto, which were named in detail and included not only the entire city of Porto, but also the Isola Lycaonia and the island with the church of S. Bartholomew, and the Transtiberine region of Rome; the grant included the complete rights over people's estates who died in his jurisdiction without an heir, or intestate, or involved in a legal situation.

The Diocese of Cære, now Cerveteri, has been united with that of Porto since the 12th century. Cære was an ancient city, called at first Agylla, where the sanctuaries of Rome and the Vestals were hidden during the invasion of the Gauls; the Etruscan tombs scattered about its territory are important archeologically. Cervetri had bishops of its own until the 11th century. The earliest known was Adeodatus, who participated in the first Roman synod of Pope Symmachus in 499. Bishop Petrus attended Pope Paul I's synod of 761; Bishop Romanus was present at Pope Eugeniius II's synod of 826; other known bishops were Adrianus (853), Crescentius (869), Annisus (995), and Stephanus (1000). The last known was Benedictus, who is recorded in 1015 and 1029.

Santa Rufina grew up around the basilica of the Holy Martyrs Sts. Rufina and Secunda on the Via Aurelia, fourteen miles (21 km) from Rome; the basilica is said to have been begun by Pope Julius I, and was finished by Saint Damasus. In the 9th century this town was destroyed by the Saracens, and the efforts of Pope Leo IV and Pope Sergius III were unable to save it from total ruin: all that remains are the remnants of the ancient basilica and a chapel.

The residence of the bishops of Silva Candida was on the Insula Tiberina beside the church of Sts. Adalbert and Paulinus, while that of the bishops of Porto was on the same island near the church of San Giovanni. The bishops of Silva Candida, moreover, enjoyed great prerogatives in relation with the ceremonies of the basilica of St. Peter. In November 1037, Bishop Petrus and all his successors were granted the office of Bibliothecarius (Librarian) of the Holy Roman Church.

The first notice of it as an episcopal see dates from the 5th century:

During the schism of antipope Clement III (Wibert of Ravenna), there was a schismatic bishop Adalbert (1084–1102), who became antipope Adalbert (1102). He was captured, brought before Pope Paschal II, and sent to the monastery of S. Lorenzo in Aversa.

Pope Callistus II (1119–1124) united to the See of Porto the other suburbicarian See of Silva Candida or Santa Rufina. The act was confirmed by Pope Adrian IV, and by Pope Gregory IX. The change is dated to 1119 by Giuseppe Cappelletti.

Historically, the Bishop of Porto became the second cardinal in terms of prestige, the Bishop of Ostia being the first, and officiated on Mondays in the Lateran Basilica; he obtained, moreover, the other rights of the Bishop of Santa Rufina, but lost jurisdiction over the Leonine City and its environs, when they were united to the city of Rome.

In 1826, Civitavecchia was separated from the Diocese of Viterbo and Toscanella and united with that of Porto, by Pope Leo XII. In 1854, it was made an independent see, but sharing a bishop with Corneto (Tarquinia) as the bishop of Tarquinia e Civitavecchia. In 1986, the two dioceses were united, becoming the Dioecesis Centumcellarum-Tarquiniensis, with its seat at Civitavecchia. The Cardinal Bishop of Porto Luigi Lambruschini (1847) restored the cathedral and the episcopal palace.

From the 16th century, the incumbency of prelates of the see of Porto was, as a rule, of short duration, because most of the cardinal bishops opted for the See of Ostia and Velletri when it became vacant. It was necessary, however, to be present at the consistory in which vacancies were being filled and cardinals could opt for Ostia in order of seniority. On 10 March 1961, in the apostolic letter Ad suburbicarias dioeceses, Pope John XXIII abolished the right of cardinal bishops to opt for other suburbicarian sees, reserving the right of appointment to the pope.

By the beginning of the 20th century, it had become apparent that the suburbicarian bishops had become overburdened with the responsibilities of their curial and diocesan duties. The increase in commerce, in roads and travel, and migration to the city, as well as the increased burden of duties in the papal administration because of the number and complexity of problems affecting the Church, made some sort of relief necessary. Pope Pius X issued a decree, Apostolicae Romanorum Pontificium, granting the bishops of Ostia, Porto, Albano. Palestrina, and Frascati each a suffragan bishop to carry the burden of their pastoral duties in their dioceses. The pope appointed the suffragans, who had full powers inside the diocese, subject to the cardinal's approval, but not the power to ordain or consecrate, or the right to have a throne or display their coat-of-arms. Further details were added by Pope John XXIII in his apostolic letter, Suburbicariis sedibus, defining the suffragan bishop as "Episcopus Ordinarius", with the same powers as other residential bishops, and enumerating the privileges of the cardinal bishop.

In 1914, Pope Pius X took steps to restrain the irregularities in the incomes of the six cardinal suburbicarian bishops. After consulting with the curial cardinals and with their agreement, he issued the decree Edita a Nobis, which ordered that in the future the incomes of the cardinal bishops should be placed in a single fund, administered by the Office of Economic Affairs, to which each cardinal must render an annual account. Each year, after 6,000 Lire was to be given to each suffragan bishop, the remaining money collected was to be divided into equal portions, the bishop of Ostia to receive two portions, and each of the other bishops one portion. The decree also ordered that the bishop of Ostia, when promoted to that position, should also retain his previous bishopric; the diocese of Velitrae was to be removed from his jurisdiction, and from that point the suburbicarin bishops would be: Ostiensis, Portuensis et Sanctae Rufinae, Albanensis, Praenestina, Sabinensis, Tusculana, Veliterna.

• Adeodatus
• Valentinus
• Tiberius (594)
• Ursus (680)
• Nicetas (710)
• Hildebrand (906)
• Peter (1026)
• Petrus (c. 1036–c. 1044)
• Crescentius (attested 1044-1050)
• Humbertus (1050–1061)
• Mainardo of Pomposa (1061–1073)

• Eugène Tisserant (1946/67–1972)
• Paolo Marella (1972–1984)
• Agostino Casaroli (1985–1998)
• Roger Etchegaray (1998–2019)
• Beniamino Stella (2020–present)

• Luigi Ermini (30 Dec 1908 – 4 Dec 1914)
• Antonio Maria Capettini, P.I.M.E. (1926–1929)
• Luigi Martinelli (13 Mar 1933 – 18 Feb 1946)
• Pietro Villa, F.S.C.J. (25 Mar 1946 – 13 Nov 1960)

• Andrea Pangrazio (1967–1984)
• Pellegrino Tomaso Ronchi (1984–1985)
• Diego Natale Bona (1985–1994)
• Antonio Buoncristiani (1994–2001)
• Gino Reali (2002–2021)
• Gianrico Ruzza (2022–present)

• Bräuer, Martin (2014). Handbuch der Kardinäle: 1846-2012 (in German). De Gruyter. ISBN 978-3-11-026947-5.
• Brixius, Johann Matthias (1912). Die Mitglieder des Kardinalkollegiums voin 1130–1181 (in German), Berlin: R. Trenkel 1912.
• Cappelletti, Giuseppe (1844). Le chiese d'Italia. Volume primo. (in Italian) Venezia: Giuseppe Antonelli,
• Gams, Pius Bonifatius (1873). Series episcoporum Ecclesiae catholicae: quotquot innotuerunt a beato Petro apostolo (in Latin). Ratisbon: Typis et Sumptibus Georgii Josephi Manz. pp. VIII–XI.
• Eubel, Conradus, ed. (1913). Hierarchia catholica (in Latin). Vol. Tomus 1 (second ed.). Münster: Libreria Regensbergiana.
• Eubel, Conradus, ed. (1914). Hierarchia catholica (in Latin). Vol. Tomus 2 (second ed.). Münster: Libreria Regensbergiana.
• Eubel, Conradus (ed.); Gulik, Guilelmus (1923). Hierarchia catholica (in Latin). Vol. Tomus 3 (second ed.). Münster: Libreria Regensbergiana. {{cite book}}: |first1= has generic name (help)
• Gauchat, Patritius (Patrice) (1935). Hierarchia catholica (in Latin). Vol. Tomus IV (1592-1667). Münster: Libraria Regensbergiana. Retrieved 2016-07-06.
• Hüls, Rudolf (1977). Kardinäle, Klerus und Kirchen Roms: 1049-1130 (in German), Tübingen: Max Niemeyer 1977.
• Jaffé, Philipp, Regesta Pontificum Romanorum ab condita ecclesia ad annum p. Chr. n. 1198 (in Latin); 2nd ed. by S. Löwenfeld, F. Kaltenbrunner, P. Ewald Vol 1. Leipzig, 1888.
• Kehr, Paul Fridolin (1907). Italia pontificia (in Latin). Vol. II: Latium. Berlin: Weidmann. pp. 17–23.
• Klewitz, Hans-Walter (1957). Reformpapsttum und Kardinalkolleg (in German), Darmstadt 1957.
• Lanzoni, Francesco (1927). Le diocesi d'Italia dalle origini al principio del secolo VII (an. 604). (in Italian) Faenza: F. Lega, pp. 110–117.
• Lentz, Harris M., III (2002). Popes and Cardinals of the 20th Century: A Biographical Dictionary. McFarland & Company, Inc. ISBN 9781476621555.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Ritzler, Remigius; Sefrin, Pirminus (1952). Hierarchia catholica medii et recentis aevi V (1667-1730). Patavii: Messagero di S. Antonio. Retrieved 2016-07-06.
• Ritzler, Remigius; Sefrin, Pirminus (1958). Hierarchia catholica medii et recentis aevi. Vol. Tomus VI (1730-1799). Patavii: Messagero di S. Antonio. Retrieved 2016-07-06. (in Latin)
• Ritzler, Remigius; Sefrin, Pirminus (1968). Hierarchia Catholica medii et recentioris aevi sive summorum pontificum, S. R. E. cardinalium, ecclesiarum antistitum series... A pontificatu Pii PP. VII (1800) usque ad pontificatum Gregorii PP. XVI (1846) (in Latin). Vol. VII. Monasterii: Libr. Regensburgiana.
• Remigius Ritzler; Pirminus Sefrin (1978). Hierarchia catholica Medii et recentioris aevi... A Pontificatu PII PP. IX (1846) usque ad Pontificatum Leonis PP. XIII (1903) (in Latin). Vol. VIII. Il Messaggero di S. Antonio.
• Pięta, Zenon (2002). Hierarchia catholica medii et recentioris aevi... A pontificatu Pii PP. X (1903) usque ad pontificatum Benedictii PP. XV (1922) (in Latin). Vol. IX. Padua: Messagero di San Antonio. ISBN 978-88-250-1000-8.

• Suburbicarian Diocese of Porto-Santa Rufina Official Website
• GCatholic
• Miranda, Salvador. "Suburbicarian Dioceses and Cardinal Patriarchs of Oriental Rite - Porto-Santa Rufina". The Cardinals of the Holy Roman Church. Florida International University. OCLC 53276621.

42°32′08″N 12°22′42″E / 42.5356°N 12.3783°E / 42.5356; 12.3783