Johannes de DeoHis name translates at "John of God". His given name may be spelled Iohannes or Joannes. Other Latin surnames besides ''de Deo'' include ''Bononiensis'', ''Ictus'' and ''Yspanus''. In other languages his name is translated ''João de Deus'' (Portuguese), ''Juan de Dios'' (Spanish), ''Giovanni di Dio'' (Italian) and ''Jean de Dieu'' (French). Se
Iohannes de Deo
in Rolf Schönberger (ed.), ''Alcuin: Infothek der Scholastik'' (Universität Regensburg, 2022). ( – 15 March 1267) was a Portuguese priest, judge and scholar of

canon law Canon law (from , , a 'straight measuring rod, ruler') is a set of ordinances and regulations made by ecclesiastical jurisdiction, ecclesiastical authority (church leadership) for the government of a Christian organization or church and its membe ...

who taught for over twenty years at the

University of Bologna The University of Bologna (, abbreviated Unibo) is a Public university, public research university in Bologna, Italy. Teaching began around 1088, with the university becoming organised as guilds of students () by the late 12th century. It is the ...

. He was a prolific writer.

Life

Johannes was called '' Hispanus'', meaning a native of the

Iberian Peninsula The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprisin ...

Patrick Colquhoun Patrick Colquhoun ( ; 14 March 1745 – 25 April 1820) was a Scottish merchant, statistician, magistrate, and founder of the first regular preventive police force in England, the Thames River Police. He also served as Lord Provost of Glasgow 1 ...

, ''A Summary of the Roman Civil Law'' (William Benning and Co., 1849), 175–176. He was born in Silves during the brief period when it was held by King

Sancho I of Portugal Sancho I (born ; Coimbra, 11 November 115426 March 1211) also referred to as Sancho the Populator (), was King of Portugal from 1185 until his death in 1211. He was the second king of Portugal. Sancho was the second but only surviving legitimat ...

between

1189 Year 1189 (Roman numerals, MCLXXXIX) was a common year starting on Sunday of the Julian calendar. In English law, 1189 - specifically the beginning of the reign of Richard I of England, Richard I - is considered the end of time immemorial. E ...

and 1191.

Christie's Christie's is a British auction house founded in 1766 by James Christie (auctioneer), James Christie. Its main premises are on King Street, St James's in London, and it has additional salerooms in New York, Paris, Hong Kong, Milan, Geneva, Shan ...

, Live Auction 6704, The Count Oswald Seilern Collection, Lot 7
Johannes de Deo (c.1190–1267), Liber poenitentiarius de cautela simplicium sacerdotum in seven books, in Latin, decorated manuscript on vellum
(2003). He refers to himself as a

priest A priest is a religious leader authorized to perform the sacred rituals of a religion, especially as a mediatory agent between humans and one or more deity, deities. They also have the authority or power to administer religious rites; in parti ...

, and seems to have been ordained in

Lisbon Lisbon ( ; ) is the capital and largest city of Portugal, with an estimated population of 567,131, as of 2023, within its administrative limits and 3,028,000 within the Lisbon Metropolitan Area, metropolis, as of 2025. Lisbon is mainlan ...

before studying at the

.Miguel Carlos Vivancos Gómez
"Juan de Dios Hispano"
'' Diccionario biográfico español'' (Real Academia de la Historia, 2018). He studied

and possibly civil law at Bologna from 1223 until 1229. His main teacher was the archpriest Zoen.A. Domingues de Sousa Costa, "Joannes de Deo", ''

New Catholic Encyclopedia The ''New Catholic Encyclopedia'' (NCE) is a multi-volume reference work on Catholic Church, Roman Catholic history and belief edited by the faculty of the Catholic University of America in Washington, D.C. The NCE was originally published in 196 ...

'', 2nd ed. (Gale, 2002), 7:882–883. He was a professor at Bologna from 1229 until at least 1255.Sam Worby, ''Law and Kinship in Thirteenth-Century England'' (The Boydell Press, 2010), 34–36. He appears to have been a

doctor of both laws A doctor of both laws, from the Latin , , or ("doctor of both laws") (abbreviations include: JUD, IUD, DUJ, JUDr., DUI, DJU, Dr.iur.utr., Dr.jur.utr., DIU, UJD and UID), is a scholar who has acquired a doctorate in both civil and church law ...

.Osvaldo Cavallar and Julius Kirshner, ''Jurists and Jurisprudence in Medieval Italy: Texts and Contexts'' (University of Toronto Press, 2020), 191 n42. The titles he uses of himself are ''doctor decretorum'' (doctor of

decrees A decree is a legal proclamation, usually issued by a head of state, judge, royal figure, or other relevant authorities, according to certain procedures. These procedures are usually defined by the constitution, Legislative laws, or customary l ...

) and ''utriusque juris professor'' (professor of both laws). In 1241, Johannes acquired a

canonry Canon () is a Christian title usually used to refer to a member of certain bodies in subject to an canon law, ecclesiastical rule. Originally, a canon was a cleric living with others in a clergy house or, later, in one of the houses within the p ...

in the

cathedral of Lisbon The Cathedral of Saint Mary Major ( or ''Sé-Catedral Metropolitana Patriarcal de Santa Maria Maior de Lisboa''), often called Lisbon Cathedral or simply the Sé ('), is a Roman Catholic cathedral located in Lisbon, Portugal. It is the oldest ch ...

. In 1247, he arbitrated a dispute in Bologna. He served as a judge on several occasions, including on occasion as a judge delegate of Popes

Innocent IV Pope Innocent IV (; – 7 December 1254), born Sinibaldo Fieschi, was head of the Catholic Church and ruler of the Papal States from 25 June 1243 to his death in 1254. Fieschi was born in Genoa and studied at the universities of Parma and Bolo ...

and Alexander IV. By March 1260, he had left Bologna to become

archdeacon An archdeacon is a senior clergy position in the Church of the East, Chaldean Catholic Church, Syriac Orthodox Church, Anglican Communion, St Thomas Christians, Eastern Orthodox Church, Eastern Orthodox churches and some other Christian denomina ...

Santarém Santarém may refer to: Places * Santarém, Pará, Brazil * Santarém District, a district in Portugal * Santarém, Portugal, Capital of the Ribatejo province * Roman Catholic Diocese of Santarém, Portugal Other * Santarém cheese, a Portuguese g ...

in the

diocese of Lisbon The Metropolitan Patriarchate of Lisbon () is a Latin Church ecclesiastical territory or patriarchal archdiocese of the Catholic Church in Lisbon, the capital of Portugal. Its archiepiscopal see is the Patriarchal Cathedral of St. Mary Major, in ...

. He continued to work as an arbitrator and judge in Portugal. One of his cases involved the monastery of Santa Cruz in Coimbra and the philosopher Pedro Julião, the future Pope John XXI. Johannes died in Lisbon on 15 March 1267.

Works

Johannes wrote numerous works in

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

on canon law: *''Casus decretalium cum canonibus concordantes''or ''Concordatis'' (before 1238), mentioned in the ''Liber iudicum'' *''Breviarium decretorum'' or ''Decretum abbreviatum'' (before 1238), mentioned in the ''Liber iudicum'', little more than a table of contents for the '' Decretum'' *''Distinctiones super toto iure canonico'' (before 1238), mentioned in the ''Liber iudicum'' *''Arbor versificata'' (before 1238), mentioned in the ''Liber iudicum'', a collection of mnemonic doggerel verse for the aid of his students, popular and widely copied *''Chronica a tempore beati Petri hucusque qualiter subcreverit ecclesia inter Turbines et Procellas'' (before 1238), mentioned in the ''Liber iudicum'' *''Liber iudicum'' (1236 or 1246), a treatise on judicial process divided into four books on judges, plaintiffs, defendants and advocates *''Epistulae canonicae de decimis'' (30 May 1240) *''Apparatus'' 'super toto corpore''ref name=PC/> ''decretorum'' (before 1241) *''Notabilia cum summis super titulis decretalium'' 'et decretorum''ref name=PC/> (September 1241), dedicated to Cardinal Gil Torres *''Casus legum canonizatarum quae inter canones continentur et unde babeant ortum in libris legalitbus'' (1 September 1242) *''Summa super quatuor causis decretorum'' (1243), a continuation of the ''Summa'' of

Huguccio Huguccio (Hugh of Pisa, Uguccio) (died 1210) was an Italian canon lawyer. Biography Huguccio studied at Bologna, probably under Gandolphus, and taught canon law in the same city, perhaps in the school connected with the monastery of SS. Nabor ...

which contains a list of his earlier works *''Liber dispensationum'' (28 August 1243), dedicated to the Dominican and

Franciscan The Franciscans are a group of related organizations in the Catholic Church, founded or inspired by the Italian saint Francis of Assisi. They include three independent Religious institute, religious orders for men (the Order of Friars Minor bei ...

orders, contains a list of his earlier works and was submitted to Innocent IV for corrections *''Liber pastoralis'' (August 1244), dedicated to Cardinal

Guglielmo Fieschi Guglielmo Fieschi was an Italian cardinal and cardinal-nephew of Pope Innocent IV, his uncle, who elevated him on May 28, 1244. He was born between 1210 and 1220 in Genoa, but nothing is known about his life before his elevation to the cardinalat ...

*''Principium decretalium'' (after 1245), an important source for the history of the Quinque compilationes antiquae *''Liber poenitentiarius'' (or ''poenitentialis'') ''de cautela simplicium sacerdotum'' (28 October 1247), a

penitential A penitential is a book or set of church rules concerning the Christianity, Christian sacrament of penance, used for regular private confession with a confessor-priest, a "new manner of reconciliation with God in Christianity, God" that was prom ...

dedicated to Bishop and heavily reliant on the ''Summa de casibus poenitentiae'' of Raymond of Peñafort, is divided into seven books containing a list of 112 sins and their corresponding

penance Penance is any act or a set of actions done out of contrition for sins committed, as well as an alternative name for the Catholic, Eastern Orthodox, and Oriental Orthodox sacrament of Reconciliation or Confession. The word ''penance'' derive ...

s, all cited to authoritative canonsRob Meens, ''Penance in Medieval Europe, 600–1200'' (Cambridge University Press, 2014), p. 212. *''Liber quaestionum'' (6 September 1248), dedicated to Cardinal Ottaviano Ubaldino *''Cavillationes'' or ''Liber cavillationum'' (2 September 1246), contains a dedication to Guglielmo Fieschi added after 1248 and a list of thirteen of his earlier works *''Concordantiae decretorum cum titulis decretalium'' (after 1248) *''Liber opinionum'' (1251), submitted to Innocent IV for corrections in October 1251 *''De abusibus contra canones'' ( n.d.), an appendix to the ''Liber poenitentiarius'' *''Catalogus haereticorum'' *''Commentum super novellis decretalium'' *''De electione'' *''Flos decretorum'' *''Lecturae super decretalibus'', readings of the ''

Decretals Decretals () are letters of a pope that formulate decisions in ecclesiastical law of the Catholic Church.McGurk. ''Dictionary of Medieval Terms''. p. 10 They are generally given in answer to consultations but are sometimes given due to the initia ...

'' *''Liber primarius de varii juris pontifici materiis'' *''Liber distinctionum'' *''Quaestiones de processu canonico'' *''Summa de sponsalibus'' *''Summa moralis'' *''Summula super decimis ecclesiasticis'', a letter to the Dominican order requesting preaching on the duty to tithe with a prologue addressed to Alexander IV and the

College of Cardinals The College of Cardinals (), also called the Sacred College of Cardinals, is the body of all cardinals of the Catholic Church. there are cardinals, of whom are eligible to vote in a conclave to elect a new pope. Appointed by the pope, ...

*''Tabula decreti'' *''Tabula decretorum'' In addition, some

glosses A gloss is a brief notation, especially a marginal or interlinear one, of the meaning of a word or wording in a text. It may be in the language of the text or in the reader's language if that is different. A collection of glosses is a ''glossar ...

on the ''Arbor actionum'' of

John Bassianus Joannes Bassianus was an Italian jurist of the 12th century. Life Little is known of his origin, but he is said by his jurist contemporary to have been a native of Cremona. He was a professor in the law school of Bologna, the pupil of Bulgarus, an ...

are attributed to Johannes de Deo. Johannes dedicated several of his works to Zoen. Although his work as a whole is not very original, it is valuable to historians for its citations of sources. It was more highly regarded and circulated widely up to the end of the 15th century. There are many manuscripts that carry his work. Johannes Andreae had a low opinion of the ''Arbor versificata'', which he said was so difficult and obscure as to make known things unknown. William Durantis relied heavily on Johannes. Johannes argued that the

Crusades The Crusades were a series of religious wars initiated, supported, and at times directed by the Papacy during the Middle Ages. The most prominent of these were the campaigns to the Holy Land aimed at reclaiming Jerusalem and its surrounding t ...

were

just war The just war theory () is a doctrine, also referred to as a tradition, of military ethics that aims to ensure that a war is morally justifiable through a series of criteria, all of which must be met for a war to be considered just. It has bee ...

s, that is, wars justified by the right of defence under

natural law Natural law (, ) is a Philosophy, philosophical and legal theory that posits the existence of a set of inherent laws derived from nature and universal moral principles, which are discoverable through reason. In ethics, natural law theory asserts ...

.Sohail H. Hashmi and James Turner Johnson, "Introduction", in Sohail H. Hashmi (ed.), ''Just Wars, Holy Wars, and Jihads: Christian, Jewish, and Muslim Encounters and Exchanges'' (Oxford University Press, 2012), 7. His ''Liber poenitentiarius'' became the new standard for penitentials. Few of Johannes' works have been printed. An exception is ''Principium decretalium'', which has been edited by

Hermann Kantorowicz Hermann Ulrich Kantorowicz (18 November 1877, Posen, German Empire – 12 February 1940, Cambridge) was a German jurist. He was a professor at Freiburg University (1923-1929), and a visiting professor, Columbia University (1927), as well as at ...

References

{{reflist, 30em 12th-century births 1267 deaths People from Silves, Portugal University of Bologna alumni Academic staff of the University of Bologna Canon law jurists 13th-century writers in Latin 13th-century Roman Catholic priests Portuguese Roman Catholic priests Canons (priests) Archdeacons