The Polish cultural legacy abroad also includes palaces and manor houses in the eastern lands of the former Commonwealth. Research is ongoing into the history of Polish noble architecture inscribed in the landscape of present-day Belarus and Lithuania.

As part of his research on Polish cultural heritage abroad, Prof. Tadeusz Bernatowicz is carrying out a wide-ranging project entitled "Rezydencje i siedziby szlacheckie w Wielkim Księstwie Litewskim. Materials for the History of Architecture'. The scope of work is unprecedented in Polish science. The researcher has set out to create a corpus of this architecture in the form of a catalogue including existing and non-existing buildings, plans of selected objects, iconography and photographic documentation of preserved palaces and manors. The whole will be accompanied by a text presenting the historical, architectural and artistic context.

In the first stage of the work, an exploratory search in the Lithuanian and Belarusian archives and preliminary field research was carried out. In 2019, Prof Bernatowicz continued his source research. At Vilnius institutions, he searched for ancestral and inventory records of the former Vilnius province (including the Main State Archives of Lithuania, the Library of the Lithuanian Academy of Sciences, the Wroblewski Library and the Lithuanian Cultural Heritage Centre). At the National Historical Archive of Belarus in Minsk, the researcher reached for manuscript source materials for research on the residences and noble residences in the historical Novogrudok voivodeship. The Moscow search at the Russian State Military-Historical Archive included old official records. In addition, archival photographic or measurement documentation of selected palaces and manors was collected (e.g. Additionally, archival photographic or measurement documentation of selected palaces and manor houses (e.g. Pruzhany, Snów, Radziwiłłmonty, Połoneczka, Zausze, Świack) was collected, as well as contemporary measurement documentation concerning projections, elevations, cross-sections (Pruzhany, Snów, Radziwiłłmonty, Świack, Zalesie, Szczorse, Postawy, Żylicze), further field surveys were carried out (Snów, Radziwiłłmonty, Połoneczka, Zausze, Zalesie, Zdzięcioł, Postawy, Karoliny), and photographic documentation was prepared. Architectural descriptions and analyses of the surveyed Polish residences and manor houses of the nobility were made for the purpose of preparing the inventory cards of the objects. As a result, a base for the development of a synthesis and a catalogue of objects was developed.

The project is being carried out jointly by the POLONIKA Institute and the Polish Institute for World Art Studies, and is scheduled to last at least 4 years.