Sadok Wincenty Barącz, known in Polish historiography as the historian of the Order of Preachers and the Armenians in Poland, was himself a descendant of Polish‑Armenians. Although he was brought up in the Armenian Catholic rite, he decided to follow the Roman Catholic priest and became a Dominican friar. His activity took place in the second half of the 19th century in various monasteries all over Galicia. Search for historical sources concerning his biography and historical work is a very difficult task, as they are scattered throughout archives and libraries in Poland and Ukraine. The author of this article made an attempt to determine their state of presentation. During the examination of Barącz’s legacy he was able to find many of his works in manuscript form, including previously unknown texts, the enormous correspondence (mostly letters received by Barącz) and the autobiography.