EN
This article examines the oldest surviving church court records from the Grand duchy of Lithuania, the First Book of Court records from the Janów Podlaski Consistory Court (Diocese of Lutsk), 1469–1486/1516. The cases studied here are but a small part of the record and were selected for their relevance to common aspects of Catholic life documented in less detail in the records of other Lithuanian dioceses (ecclesiastical endowments, adultery, devotion to the Blessed Sacrament, fraternity membership). They also provide evidence of the Faith being taught, allegedly, in Lithuanian. Seven cases are published in an appendix.