This article discusses the abacus from the pre-scholastic medieval period. Based on two descriptions dating from around 1000 (one is contained in the third volume of the Histories by Richer of Reims, and the other in the first volume of the Liber Abaci by Bernelius the younger of Paris), and mainly based on nine depictions of this counting instrument preserved in manuscripts from the late 10th to early 12th centuries (the so-called. Abacus of Echternach and the abacus of Bern - each from the late 10th century; the abacus of Paris from the early 11th century; the abacus from the work of the so-called Pseudo-Boetius, entitled Geometry II, from the mid-11th century; the abacus of the Vatican, the abacus of Rouen and the abacus of Paris - all from the 11th century; the abacus of Oxford from the early 12th century and the so-called abacus of the Abbon of Fleury), the author presents the aforementioned arithmetical device in detail. He mainly focuses on reconstructing its form based on the preserved representations and their comparison. He describes and analyzes in detail the various parts of the abacus (columns, arcs, etc.) and also presents and explains additional mathematical information appearing in the aforementioned manuscript representations of this instrument (e.g., calculator symbols, and the names of numerators, abacus column markings and fraction symbols and the relationship between them).

In this article, the author returns to the hypothesis on the sojourn of the Polish duke from the Piasts of Opole at the university in Prague. So far, the historians who believed that Bolko V in his youth studied in Prague and there acquired the title of bachelor (Polish: bakalarz) were based only on the information found in The Głogów Annals. However, an important source proving the connection of Bolko V with Prague are previously not used court trial sources, presenting a dispute between a Prague student, Henryk of Karszow and the young duke of Opole. Court files themselves only point to the fact that Bolko V stayed in Prague, where he supposedly assaulted and robbed Henryk — however, linking them to the information from the above-mentioned The Głogów Annals makes it nearly certain that the duke commenced studies in the Czech capital. Furthermore, the author hypothetically defines the date when the duke of Opole commenced studies as mid-1409 and claims he supposedly finished the studies in mid-1413.

The article shows the relationships of the Krakow town councillors with the confraternity in Saint Mary’s church. Formed around the mid‑14th century, it was the oldest and the most important one among the confraternities in the medieval Krakow. The source basis of the article is the death register of the Confraternity, published in print by Józef Mitkowski. It includes 1281 names and discloses a lot of genealogical information on the town councillors and bourgeoisie. The author describes all the councillors mentioned in the register and analyses the mentions referring to the people who were probably their relatives. He concludes that in the studied period, i.e. from the mid‑14th to the end of the 16th century, the per cent of councillors belonging to the Confraternity was 36.5%. Family members of the Krakow councillors account for 15% of all the names entered in the register. The author postulates further research on the personal composition of the confraternities in Krakow.

The objective of the article was to show the circumstances in which the peace treaty was signed by Eric of Pomerania, the king of the Kalmar Union states, and the dukes of the Western Pomerania, with the Teutonic Knights in Prussia and Livonia on 15th September 1423. The issue was analysed in the context of the relationship of the Scandinavian sovereign with the Pomeranian dukes and the bishop of Kamień Pomorski, and at the same time it was examined as a manifestation of the attempts to integrate Pomeranian duchies under the leadership of Eric. Negotiations on the covenant were initiated in the summer of 1422 and finished one year later, during the Pomeranian stage of Eric’s journey to the Holy Land. The treaty stipulated mutual military assistance in the event of a threat to one of the parties. The treaty was directly aimed against Brandenburg and indirectly against Poland, bound by a treaty with Friedrich I, margrave von Zollern. It also reinforced the positions of Pomeranian duchies and of the Teutonic order against the Brandenburg ruler. Ultimately, none of the parties issued a ratification document, which, however, did not prevent further fruitful cooperation of the Teutonic Knights with king Eric in the second half of the 1420s.

The article is a continuation of the analysis of written sources concerning Władysław Jagiełło’s tomb and some of its formal features indicating that the execution of the tomb most likely took place after 1421, and essentially before 1430, whereas it is possible that certain parts were completed already after the king’s funeral in 1434 due to the fact that the tomb (as cenotaph) was placed above his underfloor grave in the Krakow Cathedral (cf. footnote 1). The first part of this text deals with the king’s choice of the burial site in the cathedral and likely political circumstances of the heraldic and figural programme formulation on the sides of the tomb, especially in the period when Jagiełło, as the contractual and elected king of Poland and hereditary Supreme Duke of Lithuania, made attempts to secure the succession for one of his sons. The second part includes the analysis of the programme, primarily in the context of the royal sigillography, with particular attention paid to: adjusting the layout of the most significant coats of arms on the tomb to suit the location of the tomb with relation to the tomb of Saint Stanislaus, duplicating the emblems of Poland and Lithuania and exposing the coats of arms that prove the king’s achievements as regards territorial recoveries. Separate comments focus on the accompanying land coats of arms as supporters, on the representations of the court and nobility elite, especially the clergy preceding lay noblemen (archbishop — the Gniezno metropolitan bishop and most probably the Krakow bishop), distinguished as the crucial king’s counsellors when the sovereign was alive as well as guardians of the Polish Kingdom during the interregnum. The heraldic and figural decoration of the tomb is a reflection of the systemic and territorial concept of the Polish Kingdom, with which the Grand Duchy of Lithuania was united during the reign of Władysław Jagiełło (who ruled supported by his counsellors).

The development of research in the history of social communication showed a new perception of medieval correspondence as a written medium of interpersonal communication. Due to this fact, there has been a growing interest in personal letters, which previously remained overshadowed by official sources. The only paper in Poland dedicated fully to personal correspondence is still the article from 1988 by Jacek Wiesiołowski. However, numerous studies of literacy in the Middle Ages and the appearance of new source editions make it possible to formulate more theses on the social and topical scope of correspondence in Poland at that time. The conclusions were based mainly on the analysis of personal letters from four groups of sources: Private correspondence of Nicolai Serafin, a Krakow manager of salt mine, between 1437—1459, Polish documents from the archive of the Former Kingdom of Hungary (Vol. 1—5), Modus epistolandi by Jan Ursyn from Krakow and the so‑ called Krakow rhetoric. The social scope of the correspondence broadened along with the reception of pragmatic literacy (the end of the 14th century — representatives of the magnate class and municipal patricians, the 15th century — also middle levels of bourgeoisie and nobility). The most intense quantitative increase in correspondence occurred in the second half of the 15th century. The subject matter reflects a variety of topics important for people at that time (two realms: personal and business affairs). One can also observe a certain development trend: correspondence, which was originally official and related to the clergy and power elite, gradually expanded towards a more personal direction. First it was used as an instrument for business, professional and official contact and then it was noted that it can also be used for personal communication: for family, friendly and love affairs.

Mrzygłód was founded in cruda radice on the border between the Krakow voivodship and the Siewierz territory, in the area with no settlements. In 1373 there was a mention of the parish church in Mrzygłód. The origins of the parish should be linked to the formation of the town. There are reasons to ascribe the foundation of the town to Casimir the Great and to date it back to the 1350s or the 1360s. There is no evidence pointing to the Pilecki family as the founders of the town, although they are confirmed as the owners of the town since the 15th century. It is likely that they took possession of the existing settlements as a result of a royal decree at the beginning of the 15th or the end of the 14th century. The formation of the town was probably preceded by the foundation of a village called Stary Mrzygłód (Old Mrzygłód) based on the German law. Scanty sources mentioned about Mrzygłód, collected for the period until the second half of the 16th century, point to the very poor development thereof. It was a town only from the legal perspective. From the economic point of view, Mrzygłód was rather a village settlement and the inhabitants made a living mainly due to farming. The foundation process, however, allowed for colonisation of the area that was previously not touched by settlers. The colonisation of the frontier areas on the upper Warta River follows the Polish modernisation and urbanisation programme introduced and run by Władysław Łokietek and Casimir the Great.

The purpose of this text is to show the life of Dorota of Września, the second wife of the Poznań voivode, Jan Ostroróg. It also attempts to present the possibilities offered by late medieval source material as regards the reconstruction of individual stories of women from magnate class and middle nobility. In the case of Dorota, the material allowed to determine her family origins — she was the daughter of the Biechów alderman, Piotr of Września, from the Poraj family — and to show her life in the period of her marriage to Jan and afterwards, when she was a widow. The former period is depicted primarily from the perspective of her husband’s attempts to provide for the financial security of Dorota and their children: son Achilles and daughter Poliksena, in the event of his death. The time when Dorota was a widow, however, is mainly filled with court disputes with her stepchildren: Wacław and Stanisław. The subject matter of those disputes was, on the one hand, Dorota’s eventually successful attempt to recover the property, which she had received for life and which had been seized by her stepsons, as well as to punish the men for assaulting and imprisoning her. On the other hand, the stepsons accused Dorota of illegal seizure of jewellery, robes and money in silver and gold from their father’s treasury, whose part was the dowry of their mother, Helena. Based on particular source premises, the text also makes an attempt to indicate the date and reconstruct the motives and circumstances of the marriage entered into by Dorota and Jan.

The article is devoted to the functioning of a small town hall. The source basis for the research were two oldest Chrzanów municipal records, including the records from the period between 1408 and 1526. There was a search for the answers to questions related to the time when such a unit was organised in the centre undergoing the research and the functions it had with respect to the local authorities and inhabitants of the town. The milieu of town clerks was also analysed. On the basis of the sources, it was possible to identify a few of them. It was demonstrated that this function was held both by clergymen and laymen. In Chrzanów there was also one trend observed in other town as well, namely that the clerks in the town hall at the same time were teachers in the local parish school. In the period undergoing the research, the town did not have a separate room for the town hall and the documentation was stored in chests, most likely by the members of the town authorities or by the town clerk. It was observed that the Chrzanów town hall in the 15th—16th centuries followed the town hall model characteristic of other studied towns of similar size.

The article analyzes the political relations of Prandota Odrowąż, bishop of Cracow, with King Přemysl Otakar II of Bohemia in 1253-1255 in the context of a dispute over the Babenbergs' inheritance and the canonization of St. Stanislaus. Prandota, endowed with considerable authority among the mighty of Malopolska, played an essential role in political contacts with the Bohemian court. His donation of the relics of St. Stanislaus to the King of Bohemia was an act of both religious and political significance - it indicated the possibility of rapprochement between Bohemia and Lesser Poland despite the pro-Hungarian orientation dominant at the time. The author argues against the assessment that Prandota was a passive participant in the events, emphasizing his active role in building a pro-Czech orientation in Malopolska, based, among other things, on personal contacts, the interests of the Odrowąż family and the joint promotion of the cult of the new saint. Prandota tried to transplant the political ideas of the King of Bohemia to Polish soil. Still, his efforts ultimately failed - the political line based on an alliance with Hungary, promoted by Duchess Kinga, won out. The article also points to the need for further research into the role of Boleslaw the Chaste in the events described and the origins of the pro-Czech orientation in the politics of the Cracow clergy.

The authors analyze the state and importance of editing accounting sources of the Jagiellonian court, focusing on two contemporary editions - the Czech edition by Petr Kozák and the Hungarian edition by Krisztina Rábai, concerning the accounts of the court of Sigismund Jagiellon from 1493-1507. The work reveals the difficulties and imperfections in editing practice in Poland and abroad. The editions discussed here introduce essential sources on the history of administration, court culture, and finances of the late medieval monarchy into scholarly circulation. Despite the rich resource of royal accounts, Polish historiography shows insufficient interest in their compilation and publication, which contrasts with the efforts of scholars from Bohemia, Hungary, and Lithuania. Editorial solutions have been criticized, including the method of transcription, the lack of uniform and understandable designations, inconsistencies in notation, and the construction of indexes. Particular attention was paid to the problem of the lack of international accessibility of the edition (the language of the commentaries, the hermetic nature of the transcript), which limits the usefulness of the work in international scientific circulation. Despite the shortcomings pointed out, the authors express their appreciation for the editors who, working outside Poland, have done a great deal of work on sources that are also important for Polish historiography, stressing that their contribution deserves gratitude and should become an impulse for reflection on the future of historical editing in Poland.