ANGELS AROUND THE CRYSTAL
THE PRAYER BOOK OF KING WLADISLAS
AND THE TREASURE HUNTS OF HENRY THE BOHEMIAN
The fate of the codex is as mysterious as its contents. In 1630 we find it in Besançon in the possession of a certain Jacobus Prive . Twenty-four years later it is still in the same town, owned by a medical doctor called Guerinet, who asks for the Jesuit Johannes Ferrandus' opinion on the manuscript. A copy of the Jesuit's answer can be read after the text of the prayer book . These folios initiated a long scholarly debate that has not yet concluded. Ferrandus recognized clearly that the codex had been owned by a Polish king, Wladislas, and suspected that among the many Polish kings called Wladislas, it must have been the first one, Jagiello, the Grand Duke of Lithuania and creator of the Polish–Lithuanian commonwealth (Duke of Lithuania: 1377-1401, King of Poland: 1386-1434). He enumerated four arguments to support this suspicion, but admitted that this was no more than a conjecture. Just like the modern reader, the Jesuit was puzzled by the magical content of the seemingly devotional book. Furthermore, he did not see how the crystal might have been quadrangular , and he also found the crystallomantic practices to be in opposition with the Christian faith. His main concern was similar to the worries of the Paris authorities who had ordered the burning of the Liber visionum in 1323, namely the curiosity and vanity of the operator who asks for total, divine and eternal knowledge. Coming back to the history of the codex, after a half-century gap, the great book collector, Richard Rawlinson (1690-1755), purchased it at some point between 1719 and 1726, while traveling on the continent. At his death he left it to the Bodleian Library together with a huge collection of medieval manuscripts, medals and coins in 1755 (the sudden growth of the quantity of books in the Bodleian was for the librarians a real shock; for more than a century they were not even able to catalogue the Rawlinson manuscripts) .
But all this evidence is secondary to the question of who may first have commissioned the compiling of this text, that is, who Wladislas was. This name in the fifteenth century would not yet have crossed the borders of Poland, and the coat of arms present on all the miniatures clearly belongs to the Jagiello family; consequently all scholars agree that the owner of the book was one of the several Kings Wladislas known from Polish history. Traditionally, the codex is related to the Jagiellonian king of Poland and Hungary who died in 1444, in the Battle of Varna (hence it is called the Prayer Book of Wladislas Varnenczyk) . Indeed, the handwriting of the codex dates from the 1430s, while the young crowned person depicted on the miniatures resembles the king, who died as a young man in the battle: he is short, almost a child's height, and he has thick hair. This is clearly not the portrait of Wladislas II (1456-1516), King of Bohemia and Hungary, a corpuscular bald man who otherwise is also often identified as the owner of the prayer book. The miniatures, in contrast to the script, seem to date from the 1490s, the time of Wladislas II's reign . Some Hungarian philologists considered the codex to have belonged to King Matthias' Corvinian Library, which was inherited by his successor, Wladislas II. Unfortunately, these scholars have brought equally convincing arguments for both Wladislases .
The text of the prayer book, especially the ever and again repeated crystallomantic formula, is to some extent revealing about the possessor, but at the same time it adds even more confusion to the picture. Most of the prayers – in the first person singular – let slip some information on Wladislas, but not very consistently. In the crystal Wladislas wants to see the intentions and acts (consilia, acta vel facta) of not only his subjects, that is, people of lower rank who like or hate him, but also of his equals and superiors, among them kings and princes (acta vel facta superiorum dominorum meorum, regum et principum, eciam michi equalium et inferiorum subditorum meorum, qui me diligunt vel odiunt) . This means that his is not the highest place in the political hierarchy, and he is not a ruling king. He has both spiritual (ecclesiastical) and secular superiors (acta vel facta dominorum meorum superiorum spiritualium vel secularium) . Among his equals, he mainly lists dukes (eciam michi equalium ducum) , but on one occasion – rather inconsistently – even kings (acta vel facta omnium superiorum meorum, dominorum regum et principum, eciam michi equalium regum inferiorum et subditorum meum) .
Neglecting this latter example as a dictographic error, Ryszard Ganszyniec comes to the conclusion that the owner of the original text (which was, according to him, later copied in our codex) was a duke, more precisely a Silesian duke (as Ganszyniec identifies a number of Germanicisms in the text), probably Wladislas of Opole (1356-1401) . With the intention of arriving at a compromise, I propose to agree with all the arguments quoted above: in all probability the text and the book can be related to more than one Wladislas, perhaps even to three of them. To explain how this is possible, let us proceed backwards in time. The prayer book was most likely decorated in the 1490s with the Jagiellonian coat of arms in the miniatures. As is known, several unfinished codices of the Corvinian library of King Matthias were completed in Buda by the royal workshop of his successor, Wladislas II, replacing the Corvinian black raven with the Jagiellonian white eagle in the decorations . Either this prayer book was one of the inherited codices which the new king completed, or he simply brought it from Krakow to Buda as an old codex of his family (and in this case it is obviously not a Corvina), Wladislas II was certainly not its first possessor. The book was written or copied in the times of a previous king, Wladislas I (the "Varnenczyk"), adapted perhaps for his purposes. Now, either the identity of the copyist and the author coincide, and in this case we have arrived at the point of origin of the text, or the prayer book was copied from an earlier example, which may have been commissioned by a Jagiellonian duke, Opole, or the Grand Duke of Lithuania. This complicated series of owners might account for the confusing terminology of kings and dukes in the text (tt should be added, however, that if the prayer book was copied from a previous text, it is possible that the name Wladislas was inserted only in the copy, and the original text was prepared for a person of a different name). It is certain, however, that this manuscript was prepared for and circulated in the court of two or three Wladislases.
Revealing the mystery of the ownership may shed some light on the issue of the authorship. More precisely, it is not an author we are looking for, in the sense that he composed the prayers, but rather a compiler, who had a number of magical and devotional texts in front of him, and interpolated them in one final collection, incorporating the short crystallomantic formula, and substituting the usual "N" which stands for the operator in the magical literature with the name Wladislas.
This shows first of all that the Liber visionum – of which primarily Central European copies (understood in the wide sense of the word, that is, copies of north Italian, German, and Austrian provenance) were found so far  – had a certain Polish (or Silesian, or East-German) circulation in the late fourteenth or early fifteenth century. Not only was it accessible to our compiler, but also fairly profoundly known by him, and its close relationship with the Ars notoria is apparently recognized. Either our author put the two texts next to each other on his table (he may have had only a shorter version of the Ars notoria), or he had one manuscript in front of him containing both texts . We may conclude, furthermore, that our man also had a profound acquaintance with other magical experiments involving crystals, mirrors and circles.
Finally, he managed to combine two components: prayers to angels borrowed from the Ars notoria and its derivatives on the one hand, and the practice of crystallomancy on the other. For this combination no earlier example has been known to us so far than the angelic conversations of John Dee .
This person, an attentive reader of the Ars notoria and the Liber visionum, followed their terminology (as far as his own terminology can be observed at all, since he constantly incorporated alien paragraphs in his texts): he used the rare expression ars exceptiva to designate the magical arts (more precisely, he copied these words from the Liber visionum) ; he spoke about angels and (using a consciously ambivalent term) spirits, and avoided the word demones; he called the notory art ars ; he emphasized the power of words and divine names (vim et virtutem illorum verborum)  in harmony with the introductory passages of the Ars notoria. He was, furthermore, committed to the goals of his sources (for which one of them, the Liber visionum had been condemned): he sought perfect knowledge, and he wanted to know omnia secreta, que sub quatuor elementis contenta sunt.
Analyzing the transmission of manuscripts of ritual magic, Frank Klaassen points out that the scribes of these texts – in contrast to those of image magic – tended to rewrite their sources, thus creating new and new compendia . Indeed, as the Grandes Chroniques de France puts it, Brother John simply renewed a condemned heresy, although he hoped to give it another name and title . The author of Wladislas' prayer book – although not giving a new title – also used recycled prayers and definitely renewed the Liber visionum (which had renewed, in turn, the Ars notoria). The difference lies in the reception of their intellectual enterprises: the Polish compiler had a more tolerant audience than John did, and there is no sign that his work was ever condemned.
The conclusions drawn regarding John of Morigny  are analogous to what we can say about the compiler of Wladislas' prayer book. None of these persons was an outsider, a fool, or a person suffering an unstable existence. Both were clerics with a profound education, well versed in Church dialect. Both seem to be practitioners, and although the fifteenth-century compiler is not as talkative about his own experience as the fourteenth-century Brother John (or, more precisely, says nothing in his own words), both offer insight into the world of the readers and operators of the techniques of the Ars notoria. Finally, neither of them intend to write a magical handbook satisfying dubious needs. Instead, they create a genre in which it is hard to decide whether magic or religion plays the more important role (beyond this, there are many differences between the two authors – one of them is a real author, while the other is a compiler, and so on – which I will not detail here.)
We see how the author of the prayer book worked, but we still do not know who he was, nor at whose court he resided. I do not think it is very likely that the conditions he needed were at his disposal at the court of a Polish or Lithuanian duke in the fourteenth century. I would rather tend to think that the author and the copyist were not two different persons, but identical, and that our codex is not a copy but the first example of this crystallomantic prayer book. In a word, I believe that the compiler is to be found at the court of Wladislas I. Beyond this, I can only speculate, but there is an explanation which offers itself. An exceptional example of the practice of crystallomancy from the Polish Middle Ages dates precisely from the time when this codex was written. A member of the household of King Wladislas I, called Henry the Bohemian (Henricus Bohemus), was accused of and condemned for pursuing crystallomancy and keeping necromantic books. His case reminds us in many respects of those of Jean de Bar and William Byg: it is again a legal case against crystallomancy and demonic invocations, one of the chief surviving sources is again a confession in which the accused admits that he had learned the practices from magical handbooks, and the whole story is again taking place in the circles of the aristocracy, which raises the possibility that some political intrigue can account for the accusations. Henry was an influential member of the royal court, he was present at the birth of Wladislas I, and he stayed close to the future king when he was a child. Last but not least, his Bohemian origin might account for the Germanicisms of the prayer book. He was jailed in 1429, but in the 1440s he lived freely in Krakow, and he had plenty of opportunity, the necessary sources (the necromantic books) at his disposal and the background knowledge in crystallomancy to compose a royal prayer book for Wladislas.
Treasure Hunting and Crystallomancy:
The Case of Henry the Bohemian
From the acts of the legal action brought against Henry, the secrets of a group of friends and the practices of a circle of learned magicians can be disclosed . In 1429, Henry found himself accused of conjuration of demons, necromancy and the propagation of Hussite ideas. Since this was not the first occasion of such accusations against him by a court case, his life was seriously in danger, his execution a real possibility.
Henry was not an average personality of Polish history. Magister Henricus genere Bohemus – as Jan D³ugosz, the great Polish historian reports – was a talented astronomer residing at the royal court of Wladislas Jagiello from 1423 to the autumn of 1427. He was held in high respect, and he maintained a close relationship with Queen Sophie. This is shown, inter alia, by the fact that he was allowed to be present at the birth of the three sons of the king, and he even cast their horoscopes . In spite of this high esteem, Henry was accused on three different charges in 1429: inclination to the ideas of Hussitism, astrological and magical practices accomplished for finding treasure hidden in the earth (supposedly with the involvement of demons), and the keeping of forbidden necromantic books.
The court case was conducted by Stanislas of Skalbmierz (died in 1431), who – in agreement with the wishes of the court – tried to save Henry from the death waiting for him as irrecoverably heretical. Stanislas is a rather important figure of the Polish Middle Ages. He was the first rector of the renewed Krakow University, and a severe polemist in matters related to the Hussite movement, he also participated at the Council of Constance, and he was – at the time of Henry's trial – the vicar-general of the archbishop of Krakow . He was a most adequate person in this case not only because of his proficiency in theological issues related to Hussitism, but also due to his competence in magical issues, primarily concerning popular practices. In Henry's case, however, Stanislas was faced with a different set of problems: instead of folk charms and spells, instead of agricultural magic and divination from the candle, instead of midwives who did not sell milk after sunset, and superstitious women who walked around their fields with crosses, here he had to consider the methods of learned ritual magic which included necromantic books, magic circles, a crystal and a young boy.
The acts tell us that Henry attempted to search for treasures hidden in the earth with demonic help . He possessed heretical and magical books which contained heretical teachings, magical arts, divinatory procedures, invocations of demons, conjurations, interrogations and consultations in order to find treasure and other hidden things, and finally diverse errors of diviners, astrologers and sorcerers . One of these books was written by a certain Matthias, a necromancer . Both the magical books and this Matthias are still waiting to be identified in the secondary literature of medieval learned magic.
A further source, a confession made by Henry the Bohemian, complements our picture with some new details. Henry admits that he invoked demons and searched for treasure with his companions in the garden of Zwierzyniec (the zoological garden of the king). On the methods of how to conjure and bind demons, they found the instructions in necromantic books. In addition, they also practiced crystallomancy with the help of a young boy medium – again for finding treasure . Interestingly, the confession is the only source related to Henry where the child and the crystal appear: in Stanislas of Skalbimierz' text they were not mentioned, and it seems that crystallomancy was not a topic raised in the court case.
The sources give the names of some of Henry's companions: magister Nicolaus Hinczonis and magister Monaldus . The latter name refers to Monaldus de Luca, an Italian professor who specialized in mining and minting . Monaldus was expelled twice from Krakow due to his adventuresome character . His medical recipes and his short treatise on plague have been preserved in two codices of the Jagiellonan Library . As for Nicolaus Hinczonis, he originated from Kazimierz (Casimiria – a quarter of presentday Krakow) and he was also a master of Krakow University: he earned his MA degree in 1403, he was elected as rector in the winter of 1412, and he died around 1434 . Finally, a last person mentioned in the confession of Henry, a certain Stanislas, also participated in the treasure hunts; he can be identified as Stanislaus Johannis de Casimiria, who was a student in Krakow in 1408, and later a schoolmaster in Kazimierz . In short, three university masters were involved in magical activities together with Henry the Bohemian. It is logical to ask now whether he himself was a university person. Henry appears both in the Annales of Dlugosz and in the official sentence of his legal case as Magister Henricus de Brega, vocatus astrologus, laicus, which title implies that he had a university background. However, Henry is not mentioned either in the Album studiosorum or in the Liber promotionum of Krakow University, and even Stanislaus implies that Henry just abused the title of magister . Whether he brought his title from Prague is dubious and depends greatly upon the solution of another enigma: with which one of the many astronomers of Bohemian history called Henricus we want to identify him . Since there is no consensus on this question, we can only claim that at least three, but possibly four persons in the company had a university education.
It remains to examine whether there is any basis to relate the case of Henry with Wladislas' prayer book. First, the crystal-gazing and treasure-hunting methods followed by Henry and the books possessed by him indicate an equally elaborated, and in many respects similar, knowledge in the field of magic to that which we find in the prayer book containing the Ars notoria and Liber visionum prayers together with the inserted formulae on the crystal. Second, these two examples of Polish crystallomancy are strikingly close to each other in time, and what is more, we should remember that King Wladislas Warnenczyk, whom we have identified as a possible owner of the prayer book, was one of the three princes whose birth had been assisted by Henry. Finally, we see that at the end of his trial Henry avoided capital punishment, and even though he was finally jailed, somewhat later he managed to leave prison, and lived freely in Krakow . In the Acta Officialia Cracoviensis several notes report that Henricus Bohemus astronomus was active in 1440, getting involved in various official transactions with other citizens . It seems he did not completely give up his magical interest: Johannes de Dobra, a medical doctor, reports in his manuscript that Henricus Bohemus talked to him about an Armenian who lived for four hundred years thanks to a special medicine .
Being experienced in the field of crystallomancy, possessing books of magical content, a good friend of King Wladislas, and living free in the early 1440s, Henry the Bohemian could easily have been commissioned to edit a special prayer book on an omniscient crystal and on clarifying angels satisfying the "magico-devotional" purposes of the king. Taking into consideration the fact that the text of the prayer book was written precisely in the 1430s or 1440s, one could even reverse the question: who else (experienced in these fields) could have been commissioned for this task when Henry was at the court? Even though the author cannot be identified with complete certainty, at the moment Henry the Bohemian is the most plausible contender for this role. We see Henry as a most learned man in medieval magic: he might have possessed the texts of the Ars notoria and the Liber visionum, he had a close acquaintance with crystals, and what is more, his interest was apparently not limited to the field of theory: he and his friends also put their magical knowledge into practice.
Conclusion: Reading vs. Using
Finally, we may attempt to draw some conclusions from the extant crystallomantic sources regarding the reasons why they were copied at all. Were they meant to serve actual practice or mere reading? Did the scribes and owners intend to practice the divinatory procedures, magical formulae and ritual invocations? Or did they just want to learn about them, and did magic simply belong to a pure "academic interest" of the collectors? As we have seen, the answer is quite simple in the case of Henry the Bohemian: external evidence proves that he not only read in his handbooks how to rehearse crystallomancy and how to invoke demons, but also practiced it. In the case of the magical manuscripts, however, usually no definite answer can be given to the question as to whether the inclusion of magic in the codices indicates actual practices or simple curiosity. These texts contain no indication whether their scribes tried to test their instructions, and fabricated talismans or tried to create artificial monsters. Medieval folios usually do not talk to us and answer our questions concerning the intentions of their scribes.
Fortunately, the prayer book of Wladislas is not so silent, and contains internal evidence indicating actual application. While in the texts of ritual magic the operator is usually designated merely by the letter "N" (implying that the actual user has to substitute his name wherever he reads "N"), in the royal prayer book of Wladislas, "N" is always replaced with the name of the king. The source which the prayer book follows here is again the Liber visionum of John of Morigny. John gives precise instructions, according to which each person who wishes to operate with the prayers of John's book is to copy his own volume by his own hand, substituting his name for that of John, and finally he is to consecrate the book (John is aware that his name is fairly frequent, and therefore he stresses that even those persons who are also called John must reproduce the book with their own hands if they really want to use it) . Indeed, the major part of the extant copies of the Liber visionum are not mere copies of the original version, but handbooks copied and used by a certain Albertus (of Judenberg) , a Petrus , a Bernardus  and other medieval readers. Now, the substitution of the name Wladislas in the prayer book implies that the text which has come to us was made for real use, it was consecrated, and its crystallomantic formulae and angelic prayers were probably indeed applied by a certain Wladislas . It is not likely, of course, that a king copied the text with his own hands in order to render the prayers effective, but this is not a problem, because John allows that somebody else may copy the book as long as it is under the name of the prospective user . In consequence, the prayer book of King Wladislas is one of those few cases where a magical text itself betrays the fact that the book containing it was consecrated and used as a real manual.
 His name appears on f. IIr.
 F. 78v-79v. Bernacki and Ganszyniec, (eds.), Modlitewnik Wladyslawa Warnenczyka, 73-76.
 Ibid., 74: ' Crystallum nescio quam quadrilateram...'
 Madan, A Summary Catalogue, 177-178.
 Madan, A Summary Catalogue, 521; Bernacki and Ganszyniec, (eds.), Modlitewnik Wladyslawa Warnenczyka, 69-70.
 Podlacha, 'Minjatury modlitewnika Warnenczyka' [On the Miniatures of the Prayer Book].
 See Hoffmann, Régi magyar bibliofilek [Old Hungarian Bibliophiles], 49 and 164, and Csapodi, The Corvinian Library, 923. Csapodi attributes it to Wladislas I, Hoffmann to Wladislas II, both referring to the coat of arms and the crowned figure.
 Bernacki and Ganszyniec, (eds.), Modlitewnik Wladyslawa Warnenczyka, 31, 35, 38, 40, and so on.
 Ibid., 46.
 Ibid., 40.
 Ibid., 35.
 Ganszyniec, 'O Modlitewniku Wladyslawa', 70.
 Csapodi, 'Quando cessò l'attività della bottega di miniatura di Mattia?'; Csapodi and Csapodi-Gárdonyi, Bibliotheca Corviniana, 29-30. For examples of the Polish white eagle inserted in the codices of the Corvinian library, see ibid., plates XLI, LI, LVII.
 On the survived copies of the Liber visionum, see the lists of manuscripts in Fanger and Láng, 'John of Morigny's Liber visionum and a Royal Prayer Book from Poland', and in Fanger and Watson, 'Some Further Manuscripts'.
 Such as the Vienna, Schottenkloster, MS Scotensis-Vindobonensis 61, a codex copied in 1377 in which the Liber visionum (f. 1r-106v) is followed by various short Ars notoria versions (f. 107r-156r). Hübl, ed., Catalogus codicum, 74-75, and Véronese, L'Ars notoria, 145-146.
 At least, if we accept the theory of Stephen Clucas, that one of John Dee's sources was the Solomonic art. Clucas, 'John Dee's Angelic Conversations'.
 Bernacki and Ganszyniec, (eds.), Modlitewnik Wladyslawa Warnenczyka, 19 '...quod per illam artem et scienciam exceptivam errore seductus...'
 Ibid., 16, 17, 19.
[91 Ibid., 21, 23, 17.
 Klaassen, 'English Manuscripts of Magic'.
 Camille, 'Visual Art', 110.
 See Fanger, 'Plundering the Egyptian Treasure'.
 BJ 2513 and BJ 2014. For Henry and his legal process, see also the following: Zathey, 'Per la storia', especially 105-106; Birkenmajer, 'Sprawa Magistra Henryka Czecha' [The Case of Master Henry the Czech]; idem, 'Henryk le Bohemien'. For a reconstruction of the process and a critical edition of the Consilia Stanislai de Scarbimiria contra astrologum Henricum Bohemum, based on BJ 2014 f. 120r-129v (ca. 1432) and BJ 2513 f. 261r-269v (1435), see Wielgus, 'Consilia de Stanislas de Scarbimiria'.
 Dlugosz, 'Annales seu cronicae', 349-350.
 Chmielkowska, 'Stanislas de Skarbimierz'.
 'Quidam astrologus, vehementer de haeresi suspectus, generaliter omnem haeresim abiuravit; qui tamen, post abiurationem in iudicio in debita forma factam, maleficis invocantibus daemonia pro inveniendis thesauris in terra defossis per astra ad eosdem inveniendos indicavit, custodemque socii, sperans se fieri lucri participem, se fecit, bisque maleficiis illorum, qui daemonia invocabant, ut occultos thesauros invenirent, interfuit'. BJ 2014 f. 120r, Wielgus, 'Consilia', 153.
 'Quartus articulus, quod post promulgacionem sentencie episcopi et inquisitoris libros hereticos et magicos non manifestasti nec restituisti'. BJ 2513 f. 272r-278r, and Birkenmajer, 'Sprawa Magistra Henryka Czecha', 221. '...librosque tam continentes haereses, quam artes magicas aut alias divinaciones vel invocaciones demonum'. BJ 2513 f. 261r, Birkenmajer, 'Sprawa Magistra Henryka Czecha', 210; BJ 2014 f. 120r, Wielgus, 'Consilia', 154. '...necnon variae et multiplices daemonum invocationes, coniurationes, interrogationes et consultationes pro thesauris et aliis occultis inveniendis et diversi errores divinationum, astrologorum et sortilegorum'. BJ 2014 f. 125r, Wielgus, 'Consilia', 163.
 '...nonnullos cartas et libellos cuiusdam Mathie nigromantici clam in quodam hospicio receptos'. BJ 2513 f. 261r, Birkenmajer, 'Sprawa Magistra Henryka Czecha', 210; BJ 2014 f. 120r, Wielgus, 'Consilia', 154.
 'Nam ex confessione tua habetur, quod presens fuisti, cum in Kazimiria quidam negromanticus Stanislaus sedente quodam iuvene et inspiciente cristallum demones invocabat et coniurabat et responsa eorum inquirebat pro thesauris occultis in terra defossis inveniendis. Et postea in nocte ultra Zwierzyniec presens fuisti dum nigromantici similiter per nigromanciam demones adiurabant, invocabant et coniurabant, pro eidem thesauris inveniendis, et vidisti bene iuvenem sedentem et in cristallum inspicientem sed tunc invocaciones nigromanticorum non adiuvisti, quia in alia parte stetisti custodiendo, ne aliqui de villa venientes impedirent fodientes thesauros in terra quorum tu partem habere voluisti, prout habetur ex tua confessione. Scivisti eciam in libellis dicti nigromantici contineri adiuraciones, per quas demon esset compellendus ad ostendendum thesauros absconditos, prout habetur ex tua recognicione'. BJ 2014 f 138, quoted in Zathey, 'Per la storia', 105.
 'Quis dicet' - writes Stanislaus - 'hanc frequentationem non in uno, sed in pluribus, ad minus in duobus locis (quia coram teste certo et certis familiaribus magistri Nicolaus Hinczonis ac magistro Monaldo et quibusdam suis consociis) maxime iunctis aliis suspicionibus, esse modicam sive levem suspicionem, cum simplices ad credulitatem vel idiote seu minus eruditi scandalizari poterant vel infirmari in fide?' BJ 2513 f. 266v, Birkenmajer, 'Sprawa Magistra Henryka Czecha', 214; BJ 2014 f. 126v, Wielgus, 'Consilia', 166.
 His name occurs in the list of the Krakow professors, but his subject is not indicated: Pauly, Ulanowski and Chmiel, eds., Album studiosorum, vol. 1, 6. Monaldus appears also in the list of the medical doctors of the university: Hii sunt doctores et magistri: BJ 258 f. 130r- 131v. For a published version of this text, see Markowski, 'Les manuscrits des listes de docteurs', for Magister Monaldus medicus, see ibid., 137.
 He is also mentioned as a victim of a robbery: Fink, ed., Repertorium Germanicum, IV/2, col. 1876.
 BJ 792 f. 33r-42r: Monaldus de Luca, Medicinalia praecepta; BJ 849 f. 161r-162v: his tract on the plague.
 See G±asiorowski, ed., Liber promotionum, 8. Kowalczyk, 'Miko³aj Hinczowicz z Kazimierza' [Nicolaus Hinczonis of Kazimierz]. Jerzy Zathey raised the idea that this Nicolaus Hinczonis may have been identical with one Nicolaus accused of necromancy, about whom Anne of Cilli, Queen of Poland and Wladislas Jagiello's wife, wrote a letter to Pope John XXIII in 1410 mentioning him together with solis et lune figure, cristalli, cere impresse. See Zathey, 'Per la storia' 104. Indeed, the fact that both persons are mentioned as participating in crystallomantic practices in Krakow in more or less the same period makes it probable that they are identical. However, as recent research has pointed out, the first Nicolaus was a tortor, a marginal figure of the society who participated in tortures and executions, while Nicolaus Hinczonis was a university master who was rather involved in scholarly interrogations, and ths difference undermines Zathey's theory considerably. See Zaremska, Niegodne rzemioslo [Undignified Craft], 102-103.
 BJ 2014 f 138, quoted in Zathey, 'Per la storia', 105. See also Pauly, Ulanowski and Chmiel, eds., Album studiosorum, vol. 1, 27.
 Wielgus, 'Consilia', 149. For the text, see ibid., 166: Stanislas mentions some theological statement 'quod est falsum, scivit enim, quia magister est, ut asserit, in artibus...'
 For the possibilities, see Birkenmajer, 'Sprawa Magistra Henryka Czecha', 222, and Wielgus, 'Consilia', 149.
 Kowalczyk, 'Przyczynki do biografii Henryka Czecha' [Appendices to the Biography of Henry the Czech].
 Przybyszewski, ed., Cracovia artificium, vol. 1, 91-92; idem, ed., Cracovia artificium: supplementa 2, 119, 120 and 127.
 BJ 778 f. IIIv. The text is published in Kowalczyk, 'Przyczynki': 'Dominus Henricus astronomus Bohemus dixit michi de quodam Armeno, qui morabatur in Bauoria, qui vixit 400 annorum. Et magister Johannes de Ragusio cum eodem Armeno loquebatur, quomodo sic diu vitam conservaret, qui respondit, quod utebatur medicina quadam, quam idem magister Johannes de Ragusio nondum intellexit. Et hoc michi dicit idem dominus Henricus Bohemus anno Domini MCCCCXL'.
 Graz, University Library, MS 680, f. 137v col. 1: 'Quamvis liber iste sub hoc nomine iohannes conponatur et plures alij homines vocantur hoc nomine iohannes tamen nullus alius potest operari per eum nisi ille pro quo fuerit specialiter libri conpositus'.
 British Library MS 18057.
 Graz, University Library, MS 680.
 Hamilton, CA, McMaster University Library MS 107.
 For all these pieces of information and considerations, including the quotation from the Graz manuscript, I owe thanks to Claire Fanger.
 See the text of the vow which anyone has to take who wishes to recopy the book in Watson, 'John the Monk's Book of Visions', 213-214: 'Ego, nomen Christianus, famulus sive famula Yhesu Christi, ex meo libero arbitrio et voluntate propter salutem anime mee promitto omnipotenti Deo et beate Marie virgini et omnibus sanctis et electis Dei quod ego hunc librum volo met rescribere, vel alium fidelem sub nomine meo, et secundum hoc librum et institutiones suas volo facere at agere...'
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Benedek Láng (Budapest, 1974), Philosophy and History of Science Department, Budapest University of Technology and Economics, is doing research on the medieval history of science and magic, and has recently completed his doctoral thesis entitled "Learned Magic and its Readers in Central Europe in the Fifteenth Century". This article was published in "Aries" 5 (2005), nr 1 (Brill Academic Publishers).