The article deals with the issue of proving homosexuality as a cause of incapacitas assumendi on the part of the defendant in a judgment rendered in the Metropolitan Tribunal of Cracow in the third instance. The subject of the analysis is the court records from all three instances of the trial. The study is divided into three chapters, each presenting the course of evidence at the various stages of the case. In conclusion, the author attempts to assess the fairness of the conduct of the trial, drawing attention to both its strengths and weaknesses. In conclusion, it should be stated that only a fair analysis of the evidence can lead judges to achieve moral certainty regarding the invalidity of marriage.