St Magnus the Martyr, London Bridge, is a Church of England church and parish within the City of London. The church, is on the south side of Lower Thames Street near The Monument (to the Great Fire of London),See The Monument and is part of the Diocese of London and under the pastoral care of the Bishop of Fulham. It is a Grade I listed building. The rector uses the title "Cardinal Rector" and, since the abolition of the College of Minor Canons of St Paul's Cathedral in 2016, is the only cleric in the Church of England to use the title cardinal.See http://www.stmagnusmartyr.org.uk/

Saint Magnus' church lies on the original alignment of London Bridge between the City and Southwark, for centuries the only bridge between the sea and Kingston. This ancient parish was united with that of St Margaret, New Fish Street, in 1670 and with that of St Michael, Crooked Lane, in 1831.Guide to the Local Administrative Units of England I: Southern England, Youngs, F.A.: London, 1979 The three united parishes retained separate vestries and churchwardens.For example, in 1824 St Magnus the Martyr had a Select Vestry of 32 persons, whilst St Margaret New Fish Street had a General Vestry. London Parishes: Containing the Situation, Antiquity, and Re-building of the Churches Within the Bills of Mortality, Printed by Weed, B. for Jeffery, W.: London, 1824 Parish clerks continue to be appointed for each of the three parishes.The ancient office of Parish Clerk and the Parish Clerks Company of London, Clark, O.: London, Journal of the Ecclesiastical Law Society Vol. 8, January 2006

St Magnus is the guild church of the Worshipful Company of Fishmongers and the Worshipful Company of Plumbers, and the ward church of Bridge and Bridge Without. It is also twinned with the Church of the Resurrection in New York City.

Dedication The identity of the St Magnus to whom the church is dedicated is disputed. It is now dedicated to St Magnus Erlendsson, Earl of Orkney, who died in 1116 or 1117. However, scholarly opinion is increasingly coming to the conclusion that the original dedication was to St Magnus of Anagni, a 2nd-century Italian saint whose cult was widespread.

St Magnus of Orkney was executed on the island of Egilsay on 16 April in 1116 or 1117 (the year is uncertain),The Relics of St Magnus at Orkneyjar. His feast day on 16 April was included in the Missale and Breviarium Nidrosiense, i.e. of Nidaros, and the Aberdeen Breviary Aberdeen Breviary having been captured during a power struggle with his cousin, a political rival.Orkneyinga Saga: The History of the Earls of Orkney: Penguin Classics, new ed. 2004 . The Saga relates how Magnus Erlendsson, son of Erlend Thorfinnsson, accompanied King Magnus Barelegs of Norway (grandson of Harald Hardrada) during his Irish Sea Campaign of 1098, but refused to take part in the Battle of Anglesey Sound (or Menai Strait) against the Norman Earl of Chester and Earl of Shrewsbury and sang from a psalter in the midst of the fighting. As a consequence he was obliged to go into exile until after the death of King Magnus Barelegs in 1103, but was made joint Earl of Orkney with his cousin Hakon Paulsson by King Eystein Magnusson. The Irish Sea Campaign of 1098, which established the King's direct overlordship of the Kingdom of Mann and the Isles including fortifications on St Patrick's Isle near Peel, Isle of Man (see The Peel Castle Dig, Freke, D.: Douglas, 1995 ), is also described in The Chronicle of Man and the Sudreys (available at Chronicle) and in Ágrip af Nóregskonungasögum (available at Ágrip ). Magnus had a reputation for piety and gentleness and was sanctified (a form of unofficial canonisation) in 1136. St Ronald, the son of Magnus's sister Gunhild Erlendsdotter, became Earl of Orkney in 1136 and in 1137 initiated the construction of St Magnus Cathedral in Kirkwall.A Latin hymn celebrating the saint ('Nobilis, humilis, Magne martyr') survives from soon after the construction of the cathedral; see St Magnus Hymn. A lost Latin life of the saint, Vita Sancti Magni by Master Robert, thought to be Robert of Cricklade, provided material for two sagas in Old Norse. For a detailed study of the cult see St Magnus of Orkney: A Scandinavian Martyr-Cult in Context, Antonsson, Haki.: Brill, Leiden, 2007

The London church was not linked to St Magnus of Orkney before the 18th century, when it was suggested that it was either "dedicated to the memory of St Magnus or Magnes, who suffer'd under the Emperor Aurelian in 276 [this appears to be a reference to St Mammes of Caesarea, whose feast day is on 17 August],The confusion appears to have arisen because the Dominican Petrus Calo (died 1348) recounts the story of St Mammes under the heading of St Magnus the Martyr of Caesarea in Cappadocia under Aurelian with a feast day of 19 August Collectore Petro Calo Dominicano. See Bibliotheca hagiographica latina : antiquae et mediae aetatis II, p. 765, n. 5154 BHL and Bibliotheca historica medii aevi. Richard Newcourt's Repertorium Ecclesiasticum Parochiale Londinense (1708) and later works then referred to a St Magnus of Caesarea. or else to a person of that name, who was the famous Apostle or Bishop of the Orcades.""Remarks on London, being an Exact Survey of the Cities of London and Westminster, Borough of Southwark, and the Suburbs and Liberties", Stow, W.: London, 1722

For the next century most historians followed the suggestion that the church was dedicated to the Roman saint of Cæsarea."At the north east corner of London bridge, stands the parish church of St. Magnus, so named from its dedication to St. Magnus, who suffered martyrdom under the emperor Aurelian, in the city of Cæsarea, for the christian religion" – A New History of London: Including Westminster and Southwark, Noorthouck, J.: London, 1773. "There appears to have been several martyrs bearing the name of Magnus. The one to whom this edifice was probably dedicated, suffered at Caesarea in Cappadocea, A.D. 276." – The churches of London, Vol, II, Godwin, G, and Britton, J.: London, 1838. However, in the mid-19th century the prominent Danish archaeologist Professor Jens Jacob Asmussen Worsaae (1821–85) instead promoted the association with Magnus of Orkney, during his visit to the British Isles in 1846–47, when he was formulating the concept of the "Viking Age",An Encyclopedia of London, Kent, W. (ed.): London, 1937 and then in his Account of the Danes and Norwegians in England, Scotland, and Ireland of 1852.See Danes and Norwegians This theory immediately found its way into both guides and academic works.See, for example, London and Its Environs: A Practical Guide to the Metropolis and Its Vicinity, Illustrated by Maps, Plans and Views, Adam and Charles Black (1862), The hallowed spots of ancient London, Eliza Meteyard (1862), London and Westminster: City and Suburb – Strange Events, Characteristics, and Changes, of Metropolitan Life (Vol 1), John Timbs (1868), Mediaeval London Benham, W. and Welch, C.: London, 1901, and Dedications And Patron Saints of English Churches Ecclesiastical Symbolism Saints And Their Emblems, Francis Bond, 1914 Dedications. However, a guide to the City Churches published in 1917 reverted to the view that St Magnus was dedicated to a martyr of the third century: The City Churches, Taeor, M.E.: London, 1917 The discovery of Magnus of Orkney's relics in 1919 increased interest in a Scandinavian patron and this connection was encouraged by the rector who arrived in 1921.The Anglican Church Grammar School in Brisbane, Queensland, Australia was founded in 1912 by Canon William Perry French Morris – see Australian Dictionary of Biography – and dedicated to St Magnus of Orkney, but this appears to have been due to Canon Morris's support for the notion of 'muscular Christianity' rather than to any links with churches dedicated to St Magnus. The dedication to St Magnus of Orkney was confirmed by the Bishop of London in 1926.Letter dated 11 March 1926, original filed in the Registry of the Diocese of London Following this decision a patronal festival service was held on 16 April 1926.The circumstances of the dedication are described in The Times, 15 April 1926, p. 11. An exhibition relating to the history of the church was held in the following month: The Times, 31 May 1926, p. 21 The 900th anniversary of the death of St Magnus was marked with a Pontifical High Mass and Solemn Pontifical Vespers at the London church on 16 April 2016900th Anniversary of Martyrdom, parish news sheet, April 2016 (although it was to be celebrated in 2017 at St Magnus Cathedral in Orkney).

The principal argument against an association with Magnus of Orkney is that the original church pre-dated his sanctification by around a century, and was also probably constructed before the cult of St Olaf, which did not become established in London until the 1050s.The Cult of S. Olave in the British Isles, B. Dickens in Saga-Book XII of the Viking Society, 12 (1945) pp 53–80. The dedication of the church to St Magnus (as for the four City churches dedicated to St Botolph) at least partly reflected interest in particular saints' relics during the 11th century. There was a cult of this earlier (unidentified) St Magnus before the Norman Conquest: several English monastic houses claimed to have relics of the saint;These included Westminster, Peterborough and Salisbury and a relic list of Exeter Cathedral notes: "Hec sunt nomina sanctarum reliquaram que habentur in ecclesia sacte Marie et sancti Petri Exonie ecclesie, quarum maximam partem gloriossimus rex Aedelstanus eiusdem ecclesie primus fundator ibidem contulit.... De reliquiis sancti Magni episcopis et martiris."Anglo-Saxon Exeter: A Tenth-century Cultural History, Patrick W. Conner (1993). King Edgar gave one to Westminster Abbey;John Flete's manuscript history of the Abbey, written in the 1440s, records: "rex Edgarus dedit lapides quibus sanctus Stephanus lapidatus fuit, et quaedam ossa cum sanguine ejusdem; tibiam unam cum costis et aliis minutis ossibus sanctorum Innocentium ; item duas costas et terram infectam sanguine sancti Laurentii, tres costas sancti Hippolyti, dentes sanctorum Magni et Symphoriani, cum cruce sancti Felicis item reliquias sancti Georgii et Sebastiani cum aliis" The history of Westminster Abbey and the relic collection of Peterborough Abbey included the hand of St Magnus the Martyr.The Chronicle of Hugh Candidus, a Monk of Peterborough, ed. W.T. Mellows (1949). The feast of St Magnus the Martyr, celebrated on 19 August, appears in most liturgical calendars from the Gelasian Sacramentary in the eighth centurySee propers for "XIV Kal. Septembres in natali sancti Magni" Gelasian Sacramentary. The Old English Martyrology, compiled in the second half of the 9th century, records that "on the nineteenth day of the month [August] is the feast of the martyr St Magnus, whose mass can be found in the older massbooks" The Old English Martyrology: Edition, Translation and Commentary, ed. Christine Rauer, 2013. It has been suggested – see Biblical Commentaries from the Canterbury School of Theodore and Hadrian, ed. Bernhard Bischoff and Michael Lapidge (1994) – that the "older mass books" may refer more to those of Campanian origin, perhaps brought to England by Adrian of Canterbury that to the Gelasian Sacramentary. and the missal of Robert of Jumièges in the 11th century"The 'Missal' of Robert of Jumièges and manuscript illumination at Peterborough c. 1015–1035", T. A. Heslop in Peterborough and the Soke (2019). See Missal to the 16th century.See the Westminster Psalter (c.1200), the Sarum Missal, Westminster Use, Hereford breviary, The missal of St Augustine's Abbey, Canterbury, University of Oxford, Database for the Study of Latin Liturgical History and Corpus Kalendarium