Sylvias (from the Latin silva rerum, i.e. forest of things) belong to the category of domestic books manuscript books, created in Old Polish times (17th-18th century) mainly in the noble community gentry circles. They are considered a valued source for historical and literary research due to the historical and literary research due to the variety of materials they contain, collected by their authors without a specific plan according to their tastes possibilities and needs. The author of one of the largest works of this kind was Aleksander Jastkowski (c. 1625/30– c. 1691), a nobleman from the Przemyśl land Ruthenian Voivodeship, a judge of the Przemyśl lands. His sylva entitled. ‘Compendium omnis activitatis politici et rei economicae ex variis authoribus collectae’ (National Ossolineum Library in Wroclaw, manuscript no. 3554) should be considered a typical example of this type of writing. This sylva was created successively probably for more than half a century mainly by A. Jastkowski, and was completed after his death at the beginning of the 18th century by persons unknown to us. It numbers 594 pages and contains in copies numerous materials, mostly relating to public life at the time (approx. 45% of the total manuscript), such as journalistic writings, correspondence and speeches by dignitaries state dignitaries, the Diary of the Sejm of 1652, records of the Sejmik of the Ruskie Voivodeship in Sądowa and others. In addition, it contains notes by A. Jaskowski concerning his private matters, copies of his and his family’s estate documents, extracts from his and his family’s property documents, excerpts from books he had read, and notes on various fields of knowledge (cultivation of the soil, medicine, Polish and general history, legal and constitutional subjects, etc.), literary works, and notes on the history of Poland etc.), literary works, specimens and examples of occasional letters, materials concerning the private affairs of various individuals.