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Bio-Bibliographical Guide to Medieval and Early Modern Jurists

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Report No. c023




Alternative Names

Azo Portius; Azo Porcus; Azo Soldani; Azzone



Roman law jurist born as a citizen of Bologna. Studied under Johannes Bassianus, with whom he also agreed on individual positions. As a teacher, attracted many students and probably remained in Bologna; no proof exists that he taught, as sometimes supposed, in Montpellier or Provence. His students included Accursius, Jacobus Balduini, Roffredus, Martinus de Fano, Goffredus de Trano, Jacobus de Ardizione, Johannes Teutonicus, and perhaps Sinibaldo Fieschi. Appears extensively in documents from 1190 to 1220 (from 1198 always as doctor legum) showing that he was as active in the courts as he was in the classroom.

Azo was highly productive, of high reputation, and similarly had a high view of his work and himself. More than anyone else before Accursius, Azo was responsible for the spread and influence of Roman law in Europe. His Summa Codicis was especially valued and copied and printed extensively through the sixteenth century. Almost immediately it became the standard work on the Codex. He also wrote a Summa Institutionum, but it is doubtful that he was was solely responsible for the Summa on the Digest that was usually printed with these two works. The summae on the Tres libri and on the Authenticum also printed together with the other summae are not Azo’s, but belong to Placentinus and Johannes Bassianus, respectively. Azo is cited the most (c.3600 times) in the Glossa ordinaria, comprising a third of all attributed glosses. His success depended not so much on style or breadth of knowledge as on the fact that he managed to bring together the disparate elements of previous glosses and create a summary work of great systematization, objectivity, clarity, and completeness. His work also referred often to canon law. Azo frequently reworked the glosses of his predecessors and provided them with his own name. The glosses bearing his name appear under the siglum ‘Az’ or ‘az’, sometimes accompanied by a form of the surname Porcus.



No. 01

Summa Codicis, 1208–10. Although it probably relied on an earlier collection, A. most likely completed the second recension after 1208 and before a decretal from that year cited by A. was incorporated into Compilatio tertia. Summarized individual titles but also important laws. Accompanied by a prologue and a Materia Codicis. On books 1–9.

No. 02

Summa Institutionum, 1210. Probably written in conjunction with, and completed only slightly later than, the Summa Codicis; likewise composed in two recensions.

No. 03

Lectura Codicis. Survives as a reportatio copied by a student named Alexander de Sancto Aegidio. In accord with the accepted text of the Codex at the time, it is ‘complete’.

No. 04

Apparatus ad Corpus iuris civilis. Based on manuscript evidence, a widely successful work consisting of successive glosses on individual words. According to Odofredus, and confirmed by scholarship, written in two versions, the minor and the maior. Shorter apparatus written on all parts of the Corpus iuris ciuilis, but only parts of it have been found. Longer apparatus completed at least on the Digestum vetus and the Codex, possibly on other parts as well. Not printed in full; never printed in early modern edition. Edited sections include commentary on Dig. 50.17.1 De regulis iuris.

No. 06

Quaestiones. 58 known from 14 manuscripts; no manuscript contains all of them.

No. 07

Distinctiones. 100 distinctions survive in the Brussels manuscript, with 53 specifically attributed to Azo. It is likely that many, if not all, of the anonymous distinctions are also Azo’s (Seckel). Others have been located in manuscripts in Bamberg and Torino. Most have to do with the Dig. and the Cod. Described by Seckel but as yet unedited.

No. 08

Brocardica. Revision and expansion of the work of Otto Papiensis. Highly successful, most likely because A. managed to conclude each brocard with a clearly stated general rule.

No. 09

Consilia, 1205. Azo himself refers to consilia written by him in his Lectura Codicis. A single consilium is currently known, made at the request of the canons of Mosciano.

No. 10

Diffinitiones. As yet unfound; existence known from a taxation catalogue of a Bolognese book lender.

No. 11

Summa de agricolis censitis vel colonis. On Cod 1148.

No. 12

Summa de adquirendo dominio. On Dig. 41.1. Possibly Azo’s; possibly by his teacher, Johannes Bassianus.

No. 13

Summa Digestorum. The extent to which A. is responsible for the Summa on the Digest that has repeatedly been printed with his Summa Codicis and Summa Institutionum remains debated. Based on the fact that A. frequently reworked earlier works and then had his works added to by later glossators, it seems likely that A. had some hand in this Summa as well, although no known manuscript seems to preserve just his work.


Text(s) – Modern Editions

No. 01

Summa Codicis.

Modern Editions

Azonis Summa aurea, ed. (Frankfurt a.M. 1968). . (reprint of ed. Lyon 1557).


Azonis Summa super Codicem, Instituta, Extraordinaria, ed. (Corpus glossatorum iuris civilis 2; Torino 1966). . (reprint of ed. Pavia 1506).

No. 02

Summa Institutionum.

Modern Editions

Azonis Summa aurea, ed. (Frankfurt a.M. 1968). . (reprint of ed. Lyon 1557).


Azonis Summa super Codicem, Instituta, Extraordinaria, ed. (Corpus glossatorum iuris civilis 2; Torino 1966). . (reprint of ed. Pavia 1506).

No. 03

Lectura Codicis.

Modern Editions

Azonis lectura super codicem, ed. (Corpus glossatorum iuris civilis 3; Torino 1966) 1–717. (reprint of ed. Paris 1577).

No. 04

Apparatus ad Corpus iuris civilis.

Modern Editions

Edited, among others, by S. Caprioli, Glosse preaccursiane alle Istituzioni: Strato azzoniano, Libro primo . on book 1 of the Inst.


‘Azos Glossenapparat zum Infortiatum’, ed. G. Dolezalek, Ius commune 3 (1970) 191–207. (292 glosses to Dig. 34.1.8–34.5.1).


‘Azos verschollener Glossenapparat zu den Tres Partes’, ed. G. Dolezalek, ZRG Rom. Abt. 85 (1968) 407–413. (111 glosses to Dig. 35.2.83–88).


‘Tre capitoli intorno alla nozione di “regula iuris” nel pensiero dei glossatori’, ed. S. Caprioli, ASD 6/5 (1962) 356–58. (Proemium and glosses to Dig. 1.1 and 1.3).


‘Tre capitoli intorno alla nozione di “regula iuris” nel pensiero dei glossatori’, ed. S. Caprioli, ASD 6/5 (1962) 354–55. (on Cod. 1.14.1 and 3.1.8).


‘Gli apparati di azzone al digestum novum 50.17.1’, ed. E. Genzmer, ASD 1 (1957) 7–11. (on Dig. 50.17.1 De regulis iuris).


Glossen des Irnerius, ed. G. Pescatore (Greifswald 1888) 103–111. (on Cod. 1.18).


Geschichte, ed. F. von Savigny 5.627. (opening of apparatus to Dig.).

No. 06


Modern Editions

Le questioni civilistiche del secolo XII: Da Bulgaro a Pillio da Medicina e Azzone, ed. A. Belloni (Studien zur Europäischen Rechtsgeschichte 43; Frankfurt a.M. 1989) 125–72. (23 questions, 22 of which do not overlap with Landsberg’s edition).


Die Quaestiones des Azo: Zum ersten Male aus den Handschriften herausgegeben, ed. E. Landsberg (Freiburg i.B. 1888). . (19 questions; available online).

No. 09


Modern Editions

Un consulto d’Azzone dell’anno 1205, ed. L. Chiappelli (Pistoia 1888). .

No. 13

Summa Digestorum.

Modern Editions

Azonis Summa aurea, ed. (Frankfurt a.M. 1968). . (repr. of ed. Lyon 1557).


Azonis Summa super Codicem, Instituta, Extraordinaria, ed. (Corpus glossatorum iuris civilis 2; Torino 1966). . (reprint of ed. Pavia 1506).



H. Lange, ‘Azón’, in Juristas universales 1.380–4.

E. Conte, ‘Azzone’, in DGI (2013) 1.137–39.

E. Conte, ‘Vetustas: Prescrizione acquisitiva e possesso dei diritti nel Medioevo’, in Uso, tempo, possesso dei diritti, E. Conte, P. Vecchi, and V. Mannino, ed. (Università degli studi ‘Roma Tre’, Dipartimento studi giuridici 5; Torino 1999) 62–68.

H. Lange, Römisches Recht im Mittelalter 1.255–71.

E. Conte, Servi medievali: Dinamiche del diritto comune (Roma 1996).

L. Loschiavo, Summa codicis Berolinensis: Studio ed edizione di una compositione ‘a mosaico’ (Ius commune, Sonderheft 89; Frankfurt a.M. 1996) 58–61.

E. Cortese, Il diritto nella storia medievale (Roma 1995) 2.passim.

U. Gualazzini, ‘Martino, Giovanni Bassiano, Azzone nella cronaca di Giovanni prete da Cremona (XII)’, RSDI 66 (1993) 5–50.

E. Cortese, Il Rinascimento giuridico medievale (Roma 1992).

N. Sarti, ‘Una inedita quaestio azzoniana sulla restitutio in integrum del minore soccombente in possessorio (Ms. München, Bayerische Staatsbibliothek, clm 28178)’, RSDI 69 (1992) 107–44. Reprinted in: idem, Tre itinerari di storia giuridica: i manoscritti, i giuristi, gli istituti (Torino 2007) 89–136.

J. Hallebeek, ‘A Commentary of Azo upon Authentica Sacramenta puberum’, TRG 60 (1992) 289–310.

A. Belloni, Le questioni civilistiche del secolo XII: Da Bulgaro a Pillio da Medicina e Azzone (Studien zur Europäischen Rechtsgeschichte 43; Frankfurt a.M. 1989).

N. Sarti, ‘Sull’identità del dominus Iacobus qui Ianuae in equo armatus tulit sententiam: Intorno a una nuova fonte’, RSDI 62 (1989) 363–82.

E. Conte, ‘Un sermo pro petendis insigniis al tempo di Azzone e Bagarotto’, RSDI 60 (1987) 71–86.

P. Weimar, ‘Zur Entstehung der Azoschen Digestensumme’, in Satura Roberto Feenstra sexagesimum quintum annum aetatis complenti ab alumnis collegis amicis oblata, J. Ankum, F. Wubbe, and J. Spruit, ed. (Fribourg 1985) 371–92.

P. Weimar, ‘Azo’, in LMA (1980) 1.1317.

J. Fried, Die Entstehung des Juristenstandes im 12. Jahrhundert (Köln 1974) 64, 257.

P. Weimar, ‘Die legistische Literatur der Glossatorenzeit’, in Handbuch der Quellen und Literatur der neueren europäischen Privatrechtsgeschichte, H. Coing, ed. (München 1973).

G. Dolezalek, ‘Azos Glossenapparat zum Infortiatum’, Ius Commune 3 (1970) 186–207.

P. Weimar, ‘Die legistische Literatur und die Methode des Rechtsunterrichts der Glossatoren’, Ius commune 2 (1969) 69–72. Reprinted in: idem, Zur Renaissance der Rechtswissenschaft im Mittelalter (Goldbach 1997).

G. Dolezalek, ‘Azos verschollener Glossenapparat zu den Tres Partes’, ZRG Rom. Abt. 85 (1968) 403–413.

P. Stein, ‘The Formation of the Gloss “de regulis iuris” and the Glossators’ Concept of “regula”’, in Atti del Convegno internazionale di studi accursiani: Bologna, 21–26 ottobre 1963, G. Rossi, ed. (Milano 1968) 2.697–99, 714–16.

E. Cortese, La problema della sovranità nel pensiero politico medievale (Roma 1966).

E. Cortese, La norma giuridica: Spunti teorici nel diritto comune classico (Milano 1962/64) 2.175, 181-83.

P. Fiorelli, ‘Azzone’, in DBI (1962) 4.774–81.

G. Dolezalek, ‘Neue Handschriftenfunde aus Modena’, TRG 34 (1956) 407–409.

H. Kantorowicz, ‘The Quaestiones Disputatae of the Glossators’, TRG 16 (1939) 1–67. Reprinted in: idem, Rechtshistorische Schriften von Dr. Hermann Kantorowicz weiland Professor der Rechte in Freiburg/Br., Kiel und Cambridge (Karlsruhe 1970).

G. Pescatore, ‘Verzeichnis legistischer Distinktionen mit Angabe des Verfassers’, ZRG Rom. Abt. 33 (1912) 537–45.

E. Seckel, ‘Distinctiones glossatorum: Studien zur Distinktionen–Literatur der romanistischen Glossatorenschule, verbunden mit Mitteilungen unedierter Texte’, in Fs. Ferdinand von Martitz (Berlin 1911; repr. as Distinctiones glossatorum, Graz 1956) 405–419.

F. von Savigny, Geschichte 5.1–44.