In 1412, Duke Janusz I gave the dean of the chapter collegiate St. John a portion of land lying in the north of Siedlce (Sielce).In the first half of the nineteenth century, part of the land Sielc belonged to Grand Duke Constantine Pavlovich of Russia.They left a will in which his Polish estates - including Sielce - were bequeathed to Nicholas I of Russia, who was also King of Poland at the time.At the same time, the former "Principe" street was renamed Chelmska, "Lazienkowska - Nabielaka," Long "- Iwicka," garden "-Czerska," Shared "- MAGNUSZEWSKI (then Gagarin)," Okopowa "- Cadet.Warsaw Uprising: taken from T. Kondracki's article 1949: a Documentary and Feature Film center is located at Chelmska 21 1953–66: Architectural firm of Zofii Krzymuskiej-Fafius (Szczecin), George and John Zdanowicz Baumiller formed a settlement near the area of "Sielce" by Lusitanian-Czerska-Chelmska-Sielecka streets.