LTReikšminiai žodžiai: Brastos taikos sutartis; Bresto taikos sutartis; Diplomatija; Diplomatika; Dokumentų publikacija; Heraldika; Jogailaičiai (Jagiellonian dynasty); Lenkija (Lenkijos karalystė. Kingdom of Poland. Poland); Lietuvos Didžioji Kunigaikštystė (LDK; Grand Duchy of Lithuania; GDL); Sfragistika; Tarptautiniai santykiai; Vokiečių Ordinas (Teutonic Order; Kryžiuočių ordinas); Diplomacy; Diplomatics; Documents; Heraldry; International relations; Jagiellonians; Lithuania; Peace of Brzesc Kujawski; Sigillography; Treaty of Brest.
ENThe documents concerning international relationships between Lithuania and Poland of the Jagiellonian period have not been consistently explored yet. The Peace of Brześć Kujawski was signed on 31 December 1435 and was directly related to the Battle of Pabaiskas of 1 September 1435. Despite that Poland, Lithuania (Žygimantas Kęstutaitis) and the Teutonic Order had signed Treaty of Lenczyca in December 1433, it was not approved by the Livonian Order that cooperated with the dethroned grand duke Švitrigaila (Bolesław). Consequently, it was almost impossible to realise the Peace Treaty, whereas the numerous meetings did not give any results. The situation changed after the Battle of Pabaiskas. The essence of the meeting at Brześć Kujawski was to sign a treaty that would foresee 'everlasting peace' between Poland, Lithuania and Teutonic Order. The conditions of the Peace Treaty were listed in the introductions of the documents. The form of the document itself was a bent piece of paper sealed and tied with a ribbon on the left side. 13 seals were made in the first variant. The seals on the Polish and Lithuanian sides pose a lot of uncertainties, which demand further studies. The document on the side of the Teutonic Order was prepared in the same way. The German document had to be handed to the Royal Envoy in the week of Christmas, but it was passed to the bishops of Włocławek in Raciążek location.The data of signing was 1436. Below the date was an inscription explaining a mistake in one of the articles. Both sovereigns signed acts permitted to break the set conditions if the other side violated the Peace Treaty. The act of the Brest Treaty was violated a number of times, and it was followed by Erich Weise. However, no interest has been taken so far in the seals that are significant for sigillography and heraldry of Poland (and not only). The Lithuanian-Polish document consisted of three duplicates that provided a lot of useful information about the status and fate of this interesting parchment. Analysing the notarisation, it is obvious that the Peace Treaty of Brześć Kujawski was important for the Order authorities as a weapon on the international legal arena after the beginning of i3-year-long war in 1454. Therefore, this document appeared in the hands of the Order and was out of reach from military actions. Publication of the Peace Treaty of Brześć Kujawski, as well as the detailed analysis of the seals will enable to reduce the gaps in the analysis of diplomacy, deepen the knowledge of sigillography and heraldry concerning both the Teutonic Order in Prussia as well as Poland and Lithuania. [From the publication]