Chapter 6. Prologus ad Expositionem de problematibus

Chapter 6. Prologus ad Expositionem de problematibus (1318)


Cf. Repert. 5, pp. 98; MacClintock, p. 127; Schmugge, pp. 103; 128.


Mss. used here Paris, BnF lat. 6542 f. 1-268 (a. 1385); BnF lat. 15454; (ms Sorbonne 122 f. 1-181 lacks John of Jandun’s prologue).


Inc. (prol.) Iuxta sententiam Aristotelis in proemio sui libri De anima, quanto res humane perscrutationi subiecta mirabilior existit, tanto eius notitia excellentioris honestatis specie decoratur […] Hoc intelligens diligentissimus vir et doctor excellentissimus Petrus Paduensis prefatum librum Aristotelis declaravit […] (prol. Petri) Inquit magister Petrus Paduensis : Forma in hoc opere observata erit seriatim nominibus lucidis propriisque sententiis quod clausum est ex sententia in hoc libro Aristotelis exponere […] (text.) Propter quid magne superabundantie egritudinales […]

Colophon (in a different hand) ms. 6542 f. 269: Finita est expositio Petri de Abano super Problematibus Aristotelis per magistrum Johannem de Janduno declarata.



The Expositio problematum of John of Jandun has been described as a redaction (or even a commentary) of Pietro d’Abano’s Expositio problematum. It became quite popular, as shown by the fact that it has been preserved in at least ten manuscripts. The analysis given by Kuksewicz[1] in 1985 shows that only a very small part of the text, the first part of the prologue, can be ascribed to John and that the rest is a copy (with sometimes an abbreviation or addition) made by himself. Thus, we cannot speak of a commentary by John of Jandun. However, Tine Swaenepoel judges that John adapted the text in order to make it easier to understand and that we can thus consider it as a veritable revision[2].

As we have seen in John’s prologue to his commentary on the Physica, written in 1315, where he complained about the lack of a serious commentary on the Problemata, at that moment he was not yet aware of the fact that a commentary had indeed been written in Padova, by Pietro d’Abano. This scholar had published his commentary on what he considered as an authentic Aristotelian work in 1310, but he had begun working on it earlier on (during the 1290s) in Paris, and back in Padova, after his years in Constantinople, he allowed, perhaps in 1303, the circulation of a first version of the commentary[3]. The definitive version published in 1310 rapidly became influential. In 1318, John of Jandun, having received a copy of the work, published his ‘edition’[4]. As Pietro had certainly some knowledge of the Parisian arts faculty, even though he probably did not lecture there himself[5], we may suppose that Pietro d’Abano himself sent a copy of his work to John of Jandun, by the intermediary of Marsilius of Padua, as stated in the prologue (see below).

Given the minimal changes compared to Pietro’s original commentary, I will only treat the prologue. The first part of the prologue is an original composition of John of Jandun, the second part is a compilation of fragments of Pietro d’Abano’s introduction[6].

The text of Pietro d’Abano’s prologue to his Expositio has been edited by Pieter de Leemans[7]. In his introduction he gives a list of nineteen fourteenth- and fifteenth-century manuscripts; ten of them contain the ‘edition’ by John of Jandun. Among them, the manuscript Vaticano, Ottob. lat. 1764 has a colophon giving the date of the writing:


Anno Domini M°CCC°18° 6a die augusti completa fuit scriptura huius expositionis per manum Magistri Johannis de Genduno Parisius in domo scolarium de Navarra.


This seems to state that John wrote the text himself. However, one should not understand that the text in this manuscript is an autograph. It probably is a copy of the autograph. As the author of the colophon says and as John states himself (see below), he wrote his ‘edition’ with his own hand.

For the following I will use the ms. Paris, BnF lat. 6542 f. 1ra-rb; this manuscript is dated from 1385. On f. 1r we find a note in the upper margin: “Expositio Petri de Abano Paduani […] Per excellentissimum doctorem magistrum Johannem de Genduno elucidata et declarata”.

The interesting sentence quoted above (in the Introduction), in which John says that he believes to be the ‘primus inter pares’, the first among the Parisian masters of philosophy, and that he received Pietro’s commentary by the hands of his dearest friend, master Marsilius of Padua, is found on f. 1ra (last quarter):


Et ego Johannes de Genduno qui Deo gratias credo esse primus inter Parisius regentes in philosophia, ad quem predicta expositio pervenit per dilectissimum meum magistrum Marcilium de Padua, illorum expositionem manibus propriis mihi scribere dignum duxit (vel duxi), ne malorum scriptorum corruptiones dampnose delectationem meam in istius libri studio minorarent.


As explained by Kuksewicz[8], this sentence, present in two versions of the prologue, has been abridged: the first part containing the names of the two philosophers has been eliminated and the form duxit, as found in two manuscripts, has been changed into duxi in other copies. As it stands in the non-abridged version[9], we may interpret it as meaning that Pietro (sending a copy via Marsilius) has thought John worthy of copying his commentary with his own hands in order to escape scribal errors. However, the sentence is grammatically incorrect (“ego … duxit”) and the variant duxi gives an easier interpretation, that is that John himself wanted to prevent scribal errors.

Another sentence of the prologue tells us that John had the intention of “literally explaining” Pietro’s book:


Librumque prenominatum secundum illius gloriosi doctoris sententias propono Deo iubente scolaribus studii Parisiensis verbotenus explanare (f. 1ra).


This should mean that John proposed to explain Aristotle’s book, following Pietro’s opinions, in a literal commentary. This is not amazing when we consider the character of the text, which did not lend itself to a question commentary. However, we cannot know if John actually executed this project. If so, he did it orally, relying on his own ‘edition’. Or perhaps, after writing his prologue John changed his mind and simply reproduced almost exactly Pietro’s commentary.

Let us first consider the passage of the prologue to the Physica in which John had qualified the Problemata as a text worth studying:


Liber autem de probleumatibus qui ad magnam eius partem congregatus est ex multis accidentibus naturalibus manifestis ad sensum, quorum tamen cause sunt difficiles et occulte, pertine[n]t ad diversas partes scientie prenominatas, ut particula de his que sunt circa vocem adnectitur quodammodo ad secundum De anima, ubi consideratur de voce. Et similiter particula de his que sunt circa tactum quodammodo adnectitur secundo De anima, ubi agitur de tactu. Alie quoque aliis suo modo, sed de hoc non est plus ad presens. Et scias quod liber ille De problematibus communiter invenitur corruptus et incorrectus et non est multum expositus ab aliquo noto aut famoso, et ideo pauci student in eo et pauciores intelligunt eum sufficienter, quia multa et pulcherrima themata mirabilis delectationis sunt in eo / (6a) congregata ; unde indubitanter siquis illum librum bene corrigeret et exponeret competenter, multas et magnas gratias deberent ei reddere studiosi (ed. Venezia 1551, f. 5v-6r).


This book, he says, assembles a multitude of ‘natural accidents’, which are evident to the senses but of which the causes are difficult and occult. They concern various parts of the sciences, for instance the parts concerning voice or touch are connected to the second book of the De anima, and so on. And we have to know, he adds, that this book is found in a corrupted form and that is has not been much explained by well-known scholars, and therefore few people study it and still less understand it sufficiently. However, it contains many beautiful themes, and thus, if somebody would correct and explain it competently, scholars would have to be very grateful to him.

Almost a decade later, having discovered that Pietro d’Abano had done exactly this, John takes upon himself to ‘edit’ Pietro’s commentary and by doing so, to make it widely known. He adds his own prologue in a rhetorical style (as we can see in Appendix 1), preceding the one of the author[10].

In this prologue, John first stresses the amazing variety of subjects, pertaining to all parts of philosophy, in a special mirabilitatis excessus, and the admiration this book provoked among the scholars who read it. Everyone studying its copious explanations in the conspectibus universorum bonorum will become admirable and also glorious. He continues saying that this book of Aristotle, clothed in many difficulties and obscurities, was explained by the most excellent doctor Petrus of Padua, who understood its interest, in a most elegant way, not by ambition or desire of gain, but because of the natural instinct which urges every man to knowledge. And we should be grateful to him, the more so as no preceding explanation was found. We, coming after him, should not impute his prompt inquisition to audacity or presumption, but to honest love of philosophy, and we should not lacerate his work with filing tooth, but sincerely study it.

After this, John announces, using the proud formula we saw above, that he has received the commentary of Pietro d’Abano by the hands of Marsilius of Padua and that he has judged it worth transcribing in his own hand, to prevent scribal errors[11]. He also says that he has the intention to “explain the forementioned book according to the sayings of that famous doctor word for word to the students of the university of Paris” and if some things need to be added or explained, he will see to it that this is done. And although these are laborious things, he hopes that “in this (? in illo) and by him who has caused everything without labour with his perpetual deduction” these things may be profitable and that for these labours he will acquire the due gratitude of scholars.

In spite of the complex, rhetorical, and verbose style, we can understand the general meaning: this treatise (John still ascribes the Problemata to Aristotle) is eminently interesting for all parts of philosophy and it is worth being wider known. His intention was to present and comment on Peter of Abano’s commentary, after making a transcription and some corrections in his own hand, for the students. However, as we saw above, the text of his ‘edition’ cannot be qualified as a commentary[12].

Thus, we cannot use this text for the purpose of this study, since it does not show us the master before the classroom. However, the prologue, as we have seen, contains interesting information about John’s approach to this text and his admiration for the variety of subjects. We can also note that he took the time necessary to make Pietro d’Abano’s work readable for the academic community.



[1] Z. Kuksewicz, « Les Problemata de Pietro d’Abano et leur ‘rédaction’ par Jean de Jandun », in Medioevo 11 (1985) pp. 113-137.

[2] T. Swaenepoel, « Les deux versions des Problemata de Pierre d’Abano », in Filologia mediolatina 16 (2009) pp. 215-245.

[3] See the Introduction to the volume Between Text and Tradition. Pietro d’Abano and the Reception of Pseudo-Aristotle’s Problemata Physica in the Middle Ages, edited by Pieter de Leemans and M.J.F.M. Hoenen, Leuven 2016, pp. xiv-xv. See also M. van der Lugt, « Aristotle’s Problems in the West. A Contribution to the Study of the Medieval Latin Tradition », in P. de Leemans, M. Goyens (eds.), Aristotle’s Problemata in Different Times and Tongues, Leuven 2006, pp. 71-111 ; ead., « Genèse et postérité du commentaire de Pietro d’Abano sur les Problèmes d’Aristote. Le succès d’un hapax », in J.-P. Boudet et al. (eds.), Médecine, astrologie et magie au Moyen Age. Autour de Pietro d’Abano, Firenze 2013 (Micrologus Library 50), pp. 155-182.

[4] Before this date, Roger Bacon had quoted the Problemata in his Opus maius and John Vath, master of arts in Paris at the end of the fourteenth century, had used them in his commentary on the De generatione animalium ; some of them were also discussed during quodlibetical disputes at the arts faculty around 1300 ; see M. van der Lugt, « Genèse et postérité », p. 156.

[5] See ibid., pp. 164-165.

[6] Cf. Kuksewicz, op. cit., p. 118.

[7] P. de Leemans, « Ego, Petrus Paduanus, philosophie minimus alumpnorum. Pietro d’Abano’s Preface to his Expositio Problematum Aristotelis », in Between Text and Tradition (see n. 3), pp. 21-52.

[8] Kuksewicz, op. cit., pp. 119-120.

[9] Present in the mss. Paris, BnF lat. 6542 and Paris, Arsenal ms 723 (XVth century ; « Iste liber est de libraria collegii Navarre artistarum) : artistarum ».

[10] For the transcription of the Latin text, see Appendix 1.

[11] See above and the remarks of Kuksewicz.

[12] For the differences between the commentary of Pietro and the ‘edition’ by John, see Kuksewicz, op. cit., pp. 118 and 122-137.


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