ENSince the Middle Ages, Lithuania's goods were exported and goods from Western Europe were imported into Lithuania from the port city of Riga and cities of the Grand Duchy of Lithuania, Polotsk and Vitebsk, traded with Riga. From the 16 th century, merchants from the small towns and townships of Northern Lithuania and trading agents for owners of large properties - Šiaulių Ekonomija, Duchy of Biržai and others - were bringing their goods into Riga. Townspeople of Riga were also actively trading with Lithuania. However, after Riga fell to Sweden in the beginning of the 17 th century, the Swedes began introducing new customs duties, and the exporters from Northern Lithuania began changing their cargo routes. The primary partners of export manufacturers and suppliers from territories at Lithuania's north western boundary, Kretinga, Palanga and the surrounding areas of Skuodas closest to Courland harbours, were merchants from Klaipėda (Memel) and those from Liepāja (Libau) who would appear periodically. Small boats shipped cargo from these lands to Klaipėda or Königsberg. The port at Šventoji became more active during the end of the 17 th century and it was also starting to compete with the Courland and Livonia ports. However, Swedes destroyed this har bour right at the start of the 18 th century during the Great Northern War. There has not been any special investigation regarding Lithuania's trading contacts with Courland's ports yet. It is possible to find one or another fact regarding relationships between Lithuania and Courland in historical literature but not in the context of trading. Overall there has been scant research on Lithuania's trade in the 18 th century excepting the one study on the foreign trade of the Lithuanian Grand Duchy in 1785-1792 . This study contains very generalized data covering a very short time span. It does not even indicate the specific significance of Courland's ports.