The article provides information on Ostrog, located in Ukraine, which at the time of writing was under the rule of the Jablonovskis. The past of Ostrog is recapitulated in the text, starting from the Ruthenian beginnings, through the stage of the Polish-Lithuanian Commonwealth, and finally to the last owners of this estate. (Source: Tygodnik Illustrowany, Warsaw 1862, T:5, pp. 124-125., after: Digital Library of the University of Łódź)