Acta Historica Universitatis Klaipedensis

The paper analyses the impact of his interest in 19th-century East Prussian ethnic culture on the activities of Richard Jepsen Dethlefsen (1864–1944), one of the pioneers of monument protection in the region. Dethlefsen’s important activity in the area of recording and protecting the East Prussian cultural heritage also implied an acquaintance with the cultural values of Prussian Lithuania, whose roots were formed by the Reformation in the Duchy of Prussia; by Romanticism, which actualised the history of Prussia and the Prussian tribes; and a few other factors. Despite the impact of nationalism paradigms in the German Empire in the late 19th century, Dethlefsen’s activities contributed to the understanding of the intentions of his contemporaries to consider East Prussia as a unique cultural space, whose historical conditions predetermined the survival of the uniqueness of several ethnic regions, by emphasising it as a value of the East Prussian province to be protected. The concept of pluriculturalism of the former East Prussia, as revealed in Dethlefsen’s work, remains a relevant guideline for cultural heritage policy in west Lithuania (the former Klaipėda region).