The article is based on previously unexplored sources from the Ecclesiastical Archives of the Wrocław Archdiocese Archive and, to a lesser degree, those stored in Katowice. In 1936, Bishop Adolf Bertram, long-time head of the Wrocław Diocese, decided to prepare a strategy aimed at securing the collections and archival materials of the more than 1,000 subordinate parishes in order to prevent them from being exploited by the Third Reich for the purpose of pursuing its racist policies. To that end, in 1936, the Wrocław Curia introduced special procedures related to handling files and appointed dozens of archival science experts in the parishes. These experts began to categorise and develop an index list of old files in the form of a special registry. The files themselves were transferred to the Archdiocese Archive in Wrocław in order to protect them. Cardinal Bertram prohibited the parishes from making any archival materials in their possession available to the public. Unexpectedly, between 1936 and 1939, Wrocław Church archivists were able to enter into a partnership with the German State Archive in Wrocław, which helped protect the Church’s collections and lasted until the end of the war in 1945. The article presents the most important events related to this partnership which occurred between 1936 and 1939.