The article presents the results of the latest research on the late-Gothic triptych in the church of St. Thomas in Nowe Miasto Lubawskie. Despite its importance as being one of only two preserved medieval altars in the Chełmno region, this monument has not been analysed in a monograph. Based on the analysis of modern source texts as well as later references and photographs, the place of its functioning up to the 20th century was analysed. Later, the triptych was transferred to the Seminary in Toruń. Based on the investigation of old illustrations, descriptions and conservation documentation, outlining the history of the transformations of the monument was attempted. After conducting a stylistic analysis, it was argued that it is possible to link the Nowe Miasto triptych with Toruń workshops and date its creation around the second decade of the 16th century.