The article describes 16 open letters of the Lübeck City Council, kept in the Russian State Archives of Ancient Documents, and issued to the Hanseatic merchants travelling to Russia, and confirming the Hanseatic origin of the goods transported across the border. The contents of the open letters are analyzed to identify the main features of the Russian-Hanseatic trade after the end of the Livonian War and before the signing of the Trade Peace Agreement of 1603, which established the rules of the Hanseatic-Russian commodity exchange and the list of the German merchants’ privileges in the Russian markets. Much attention is paid directly to the merchants who were given the open letters to determine their connection with the Corporation of Lübeck’s “Novgorod guests” (Nowgorodfahrer), a Lübeck burghers’ large commercial association that occupied an important place in the Russian–Hanseatic trade of the late Middle Ages and the early Modern Times. The subject of research in that respect were manuscript materials from the Archives of the Hanseatic city of Lübeck have become the subject of the research work. Moreover, the 1594 open letters of the Lübeck Magistrate from the Russian State Archives of Ancient Documents are compared with the similar documents of the period under review from the Tallinn City Archives. The original text of one of the open letters is appended to the article, as well as the drawings of the possessory signs of the Hanseatic merchants depicted in the studied handwritten sources.