Conservation works under Conrad Steinbrecht involving a late Gothic Saint Wolfgang triptych from the Parish Church in Toruń’s Old Town have not seen sufficient research interest to date. A brief 1912 account by Bernhard Schmid remains the only source used today. The Toruń Art Inventory project with a focus on the Historical Records Archives of the Toruń Diocese led to a discovery of 19 letters penned by Steinbrecht to the parish priest of Toruń. Once analysed, the correspondence allowed a somewhat more accurate identification of the contemporaneous scope of conservation works, including their dates and duration (1909-1911), and individual work stages. In addition, the analysis shed new light on the history of creating a new main retable for the castle church in Malbork.