The first problem encountered in any scholarly study is that of scope. The topic of research must be sufficiently extensive to make it of general use, but specific enough to allow adequate coverage, given the limitations of length and time. The objective of the present work has been restricted, in the first instance to a description of the commercial relationship between England and the Polish Commonwealth, and secondly to an explanation of the decline in that relationship. This concentration on the Anglo-Polish link in a study of England's Baltic trade is easily justified, as, at the beginning of the seventeenth century, almost 85 per cent of English shipping in the Baltic was directed to the ports of the Polish Commonwealth. Furthermore, the first half of the seventeenth century is a period which begins with English commerce securely established in the ports of Elbing and Danzig, and ends with the failure of these ports to maintain their virtual monopoly of trade with England. Hidden within this phenomenon is the broader failure of the Polish economy to preserve its commercial relationship with England and the failure of English mercantilists (notably the Eastland Company and the royal government) to resist the pressure on their merchants to trade elsewhere while simultaneously resisting Polish attacks on their privileges.

Such close definitions carry with them certain inevitable consequences. Commercial relations are the key to this study, and therefore other factors such as ordinary diplomatic incidents, negotiations for dynastic alliance through marriage, and contacts through third parties such as Courland, Brandenburg and the Ottoman Empire, have of necessity been ignored except where they can be demonstrated to have a commercial dimension.