A collection of letters of Józef Kremer and his family from approx. 1830-1894, hitherto considered to be lost, was found by Alina Baran in the Congregation of the Mission (Vincentian Fathers) Archives in Cracow in 2015, where it has been kept for several decades. The collection consists of two parts. The first one is composed of over 790 manuscript pages, the other one, of several dozen typescript pages (the majority of which has been known and even appeared in print). The manuscript part comprises over 150 letters addressed to J. Kremer, the family correspondence (over sixty items) and numerous miscellanea. It is the most valuable - because hitherto unknown - part of the correspondence of the Kremer family.