Fagan (; ), also known by other names including Fugatius, was a legendary 2nd-century Welsh bishop and saint, said to have been sent by the pope to answer King Lucius's request for baptism and conversion to Christianity. Together with his companion St Deruvian, he was sometimes reckoned as the apostle of Britain.

King Lucius's letter (in most accounts, to Pope Eleutherius) may represent earlier traditions but does not appear in surviving sources before the 6th century; the names of the bishops sent to him does not appear in sources older than the early 12th century, when their story was used to support the independence of the bishops of St Davids in Wales and the antiquity of the abbey at Glastonbury in England. The story became widely known following its appearance in Geoffrey of Monmouth's pseudohistorical History of the Kings of Britain. This was influential for centuries and its account of SS Fagan and Deruvian were used during the English Reformation to support the claims of both the Catholics and Protestants. Geoffrey's account is now considered wholly implausible, but Christianity was well-established in Roman Britain by the third century. Some scholars therefore argue the stories preserve a more modest account of the conversion of a Romano-British chieftain, possibly by Roman emissaries by these names.

Fagan is the patron saint of a number of churches, and gives his name to the village St Fagans near Cardiff, now the home of a Welsh National History Museum. His feast day does not appear in any medieval Welsh calendar of the saints and is not observed by the Anglican, Catholic, or Orthodox churches in Wales.

Name St Fagan's name appears as "Phagan" () in William of Malmesbury's work On the Antiquity of the Glastonbury Church, written between 1129 and 1139. It is given as "Fagan" () in Geoffrey of Monmouth's pseudo-historical History of the Kings of Britain, written around 1136 and sometimes supposed to have been the source of the name's later insertion into William's account. The name has been variously connected with Latin paganus ("rural, pagan"), French faguin ("faggoter, wood gatherer"), and Old English fagin ("joyful").Gold, David L. "Jewish Dickensiana, Part One: Despite Popular Belief, the Name Fagin in Charles Dickens's Oliver Twist Has No Jewish Connection" in Studies in Etymology and Etiology, p. 767. University of Alicante Press (San Vicente), 2009. . Wade-Evans proposed that the name was a confusion with the Italo-British rhetorician Bachan or Pachan who appears in the life of Saint Cadoc.Bartrum, Peter C. "Bachan" in A Welsh Classical Dictionary: People in History and Legend up to about A. D. 1000, p. 38. National Library of Wales, 1993. Emended 2009.

The entry on Pope Eleutherius in Petrus de Natalibus's late 14th-century collection of saints' lives gives Fagan's name as "Fugatius",Petrus de Natalibus. "Eleutherius Papa" ["Pope Eleutherius"] in Catalogus Sanctorum [Catalog of the Saints], Vol. V, Ch. xlvi.  1406, 1st printed (Vicenza), 1493. Reprinted Giacomo Giunta (Lyon), 1543. an emendation subsequently copied by PlatinaPlatina. Vitæ Pontificum Platinæ Historici Liber de Vita Christi ac Omnium Pontificum qui Hactenus Ducenti Fuere et XX [Platina the Historian's Lives of the Popes: A Book on the Life of Christ and All the Popes Since who Are Two Hundred and 20], p. 25. Johann von Koln & Johann Manthen von Gerresheim (Venice), 1479. Platina. Translated by Paul Rycant as Lives of the Popes, from the Time of Our Saviour Jesus Christ to the Reign of Sixtus V. (London), 1685. Edited and reprinted as The Lives of the Popes from the Time of Our Saviour Jesus Christ to the Accession of Gregory VII, Vol. I, pp. 33–34. by Griffith, Farran, Okeden, & Welsh (London), 1888. and many others.Jacobus Usserius [James Ussher]. Britannicarum Ecclesiarum Antiquitates, Quibus Inserta Est Pestiferæ Adversus Dei Gratiam a Pelagio Britanno in Ecclesiam Inductæ Hæreseos Historia [Antiquities of the Britannic Churches, into Which Is Inserted a History of the Pestilent Heretics Introduced against the Grace of God by Pelagius the Briton into the Church], Ch. IV. (Dublin), 1639. Reprinted in The Whole Works of the Most Rev. James Ussher, D. D. Lord Archbishop of Armagh and Primate of All Ireland, Vol. V, pp. 74 f. Hodges, Smith, & Co. (Dublin), 1864. These names were further misspelled in later sources in a variety of ways.

Sources The story of Pope Eleutherius's late-2nd-century mission to the apocryphal King Lucius of Britain (Welsh: Lles ap Coel) dates to at least the 6th-century recension of The Book of Popes known as the "Felician Catalog" but the names of the missionaries themselves don't seem to have appeared before the 12th century. They aren't given by Bede's 8th-century Ecclesiastical History of the English PeopleBeda Venerabilis [The Venerable Bede]. Historia Ecclesiastica Gentis Anglorum [The Ecclesiastical History of the English People], Vol. I, Ch. IV, & Vol. V, Ch. XXIIII. 731. Hosted at Latin Wikisource. Bede. Translated by Lionel Cecil Jane as The Ecclesiastical History of the English Nation, Vol. 1, Ch. 4, & Vol. 5, Ch. 24. J.M. Dent & Co. (London), 1903. Hosted at Wikisource. or by the 9th-century History of the Britons traditionally credited to Nennius."Nennius". Edited by Theodor Mommsen. Historia Brittonum, Vol. II, Ch. xxii. . Hosted at Latin Wikisource. "Nennius". Translated by J.A. Giles & al. as Nennius's History of the Britons, §22, from Six Old English Chronicles of Which Two Are Now First Translated from the Monkish Latin Originals: Ethelwerd's Chronicle, Asser's Life of Alfred, Geoffrey of Monmouth's British History, Gildas, Nennius, and Richard of Cirencester. Henry G. Bohn (London), 1848. Hosted at Wikisource. William of Malmesbury's 'third edition' of the Deeds of the Kings of the English () records of the priests sent to Lucius that "the rust of antiquity may have obliterated their names".Gulielmus Malmesburiensis [William of Malmesbury]. Gesta Regum Anglorum. . William of Malmesbury. Translated by J.A. Giles as William of Malmesbury's Chronicle of the Kings of England from the Earliest Period to the Reign of King Stephen, p. 21. Henry G. Bohn (London), 1847.

However, the work On the Antiquity of the Glastonbury Church,Gulielmus Malmesburiensis [William of Malmesbury]. De Antiquitate Glastoniensis Ecclesiæ. 1129–1139. Hosted at the University of Zurich's Corpus Corporum. initially written by William between 1129 and 1139,Robinson, Joseph Armitage. "William of Malmesbury 'On the Antiquity of Glastonbury'" in Somerset Historical Essays. Oxford University Press (London), 1921. Hosted at Wikisource.Newell, William Wells. "William of Malmesbury on the Antiquity of Glastonbury, with Especial Reference to the Equation of Glastonbury and Avalon" in Publications of the Modern Language Association of America, Vol. XVIII, No. 4. 1903. and Geoffrey of Monmouth's History of the Kings of BritainGalfridus Monemutensis [Geoffrey of Monmouth]. Historia Regnum Britanniae [History of the Kings of Britain], Vol. IV, Ch. xix–xx. . Geoffrey of Monmouth. Translated by J.A. Giles & al. as Geoffrey of Monmouth's British History, Vol. IV, Ch. XIX–XX, in Six Old English Chronicles of Which Two Are Now First Translated from the Monkish Latin Originals: Ethelwerd's Chronicle, Asser's Life of Alfred, Geoffrey of Monmouth's British History, Gildas, Nennius, and Richard of Cirencester. Henry G. Bohn (London), 1848. Hosted at Wikisource. both include the names of Fagan and his companion. A contemporaneous or even earlier source is the letter of the convent of St David's to Pope Honorius II preserved in Gerald of Wales's Book of InvectivesGiraldus Cambriensis [Gerald of Wales]. De Inuectionibus [On Invectives], Vol. II, Ch. X, in Y Cymmrodor: The Magazine of the Honourable Society of Cymmrodorion, Vol. XXX, pp. 143–6. George Simpson & Co. (Devizes), 1920. Gerald of Wales. Translated by W.S. Davies as The Book of Invectives of Giraldus Cambrensis in Y Cymmrodor: The Magazine of the Honourable Society of Cymmrodorion, Vol. XXX, pp. 17–8. George Simpson & Co. (Devizes), 1920. which appears to date from the 1120s. Geoffrey claimed to have derived his own account from a 6th-century treatise by St Gildas on "the victory of Aurelius Ambrosius"; given the content of his story, the claim is generally discounted. After these, the story began to be broadly repeated. Further details appeared in the Iolo Manuscripts collected by Edward Williams, although his many alterations and forgeries render their historicity suspect.

The discrepancy in William's accounts led Robinson to conclude that the appearance of the missionaries' names in the earlier book was a spurious addition by the abbey's scribes, of a piece with the passages in the present text that include a patently fraudulent "Charter of St Patrick", that describe Abbot Henry of Blois ( 1171) as "of blessed memory", and that mention a fire which occurred at the abbey in 1184. Robinson and Bartrum proceed to treat Fagan as an invention of Geoffrey subsequently taken up by others.Bartrum (2009), "Ffagan", p. 298. Baring-Gould, Rees, and Mullins modify this somewhat: while admitting misinformation in the account of Geoffrey, they suggest that the names of Fagan and his companions were probably genuine but that—in the absence of more detailed surviving records—they had been taken up and added to the legendary accounts of King Lucius.Baring-Gould, Sabine & al. The Lives of the British Saints: The Saints of Wales and Cornwall and Such Irish Saints as Have Dedications in Britain, Vol. III, pp. 9–10. Honourable Society of Cymmrodorion (London), 1911.Mullins, Daniel J. Early Welsh Saints, p. 30. Carreg-Gwalch Press, 2003.

Legend

Accounts of St Fagan and his companion Deruvian joined a long-standing narrative concerning King Lucius of Britain and his conversion to Christianity around the time of the Roman Emperors Antoninus Pius and Marcus Aurelius, a time of general tolerance towards the religion. St Gildas had described the first apostles as arriving during the reign of the emperor Tiberius.Gildas. De Excidio et Conquestu Britanniae [On the Ruin and Conquest of Britain]. Translated by Thomas Habington as The Epistle of Gildas the most ancient British Author: who flourished in the yeere of our Lord, 546. And who by his great erudition, sanctitie, and wisdome, acquired the name of Sapiens. in 8 vols. T. Cotes for William Cooke (London), 1638. Edited and reprinted by John Allen Giles as "The Works of Gildas, Surnamed 'Sapiens,' or the Wise", §VIII, in Six Old English Chronicles of Which Two Are Now First Translated from the Monkish Latin Originals: Ethelwerd's Chronicle, Asser's Life of Alfred, Geoffrey of Monmouth's British History, Gildas, Nennius, and Richard of Cirencester. Henry G. Bohn (London), 1848. Hosted at Wikisource. William of Malmesbury's cautious account in the Deeds of the Kings of the English allows that St Philip may have reached the island but quickly leaves such "vain imaginations" in favor of praising the ancient wattle chapel of St Mary erected by Pope Eleutherius's nameless missionaries, which he called "the oldest I am acquainted with in England". (The precise antiquity of the church was part of a bitter dispute over seniority between the abbey and Westminster over the primacy of their foundations.)

The current text of On the Antiquity of the Glastonbury Church is rather more florid: Philip is not said to have come himself but to have sent Joseph of Arimathea in precisely AD 63. His initial community died out and the area left to "wild beasts" but "Phagan" and Deruvian found it miraculously preserved, merely reviving its community in AD 166, directed by the Archangel Gabriel and joining their names to the Acts of the Apostles. They were said to have provided pilgrims with 40 years of indulgences, a wildly anachronistic detail, but one quite profitable for the abbey.