So far, historiography has not paid much attention to the synod that took place in Łęczyca in 1402. Information about it is contained in a document of the vicar general of Gniezno, Mikołaj Strzeszkowic, issued in Gniezno on December 16 of that year, calling on the clergy of the Archdiocese of Gniezno to pay the tribute imposed at that synod by the archbishop Mikołaj Kurowski. Previous knowledge on this subject was limited only to the fact of its adoption and the contribution specified therein. However, there is a document dated in Łęczyca on November 29, 1402, in which the Archbishop of Gniezno, Mikołaj Kurowski, and other bishops grant 40 days of indulgence to the faithful who meet certain religious conditions or materially support the newly founded hospital and monastery of the Order of Preachers in Płock. This indicates the connection of this document with the synod, suggesting that the synod took place at the end of November 1402. Archbishop Mikołaj Kurowski and six bishops were present at the synod. The main resolution of the synod was to adopt a contribution in the area of the Gniezno diocese. Mikołaj Strzeszkowic was appointed the main tribute collector. Collecting money was difficult, so on December 16, 1402, Strzeszkowic called on the clergy to fulfill this obligation. Due to further resistance from the clergy, Archbishop Mikołaj Kurowski placed Gniezno under an interdict. To sum up, the synod of Łęczyca took place at the end of November 1402, during which the contribution in the area of the Gniezno diocese was adopted, and the clergy were called to fulfill it under the threat of interdict. The further course of these events is unknown.