Lech Mroz, head of the Institute of Ethnology and Cultural Anthropology, University of Warsaw, analyses 166 original and previously unpublished documents dating from the very first mention of a Gypsy in 1401 up to the year 1765. These documents range from royal decrees through lawsuits to entries in municipal records. Some were written in Polish but many are in Latin, German or Ruthenian. They tell the story of not only the Gypsies living in Poland, but also of those who now live in Belarus, Lithuania, Latvia and Ukraine.
For more information, see http://ceupress.com/books/html/Roma_Gypsy_Presence.htm