Źródła do dziejów Rzeczypospolitej Obojga Narodów w okresie rządów Wazów i „królów rodaków” w Archiwum Książąt Kurlandzkich w Łotewskim Państwowym Archiwum Historycznym w Rydze

The article discusses the holdings of the princes of Courland Archives , which is stored - as fond 554 - at the Latvian State Historical Archives (Latvijas Valsts vestures arhivs) in Riga. So far, the Polish historians have used these records to a small extent., although this archive contains many valuable materials for the history of the Polish-Lithuanian Commonwealth in the 17th century. The most valuable Polonica include a vast collection of correspondence between the princes of the Kettlers Family and the Polish kings of the Vasa dynasty as well as with the leading representatives of the Polish and Lithuanian magnates. This collection includes some interesting source material for the history of the military conflict with Sweden, as of the campaign of 1621, until the end of the Second Northern War in 1660. Great value have also diplomatic records, mostly reports submitted by the representatives of the Kettlers at the royal court (especially of Jan III Sobieski), as well as documents showing the policy of the princes of Courland towards its neighbors (Poland, Moscow, Sweden, Brandenburg), and their attempts to appear neutral and independent in times of great conflict taking place in the 17thc. in this part of Europe.