The Danish Sound and the Hanseatic League
The Danish Sound, the narrow strait between Denmark and Sweden, was the principal gateway between the Baltic and the North Sea, and the Sound was the principal source of the League’s commercial dominance. The Sound was, in the medieval period, the only practical route for seagoing vessels to enter or leave the Baltic, and the control of the Sound was, accordingly, one of the most important strategic objectives of the great powers of northern Europe.
The tolls and the Danish kings
The Sound was, in the first instance, controlled by the kings of Denmark, and the Danish kings were able to levy tolls on the vessels that passed through the Sound. The Sound’s tolls were, in the late Middle Ages, one of the principal sources of revenue for the Danish crown, and the tolls were the principal source of the wealth of the Danish kings. The tolls were, however, also a major source of friction between the Danish crown and the League, and the tolls were one of the principal causes of the wars between the League and the Danish crown.
The League’s response
The League’s response to the Danish tolls was, in the first instance, diplomatic. The League negotiated a series of treaties with the Danish crown that regulated the tolls and that granted the League’s merchants a privileged position in the Sound. The treaties of 1367–70 (the Treaty of Stralsund) and 1426–35 (the Treaty of Vordingborg) were particularly important, and the treaties gave the League a substantial role in the governance of the Sound.
The League’s response to the Danish tolls was also military. The League fought several wars with the Danish crown over the Sound, and the League’s victories in these wars gave the League a substantial control over the Sound. The League’s fleet was the principal naval force in the Baltic, and the League’s fleet was used to enforce the League’s policies in the Sound. The League’s fleet was also used to blockade the Danish ports, and the blockade put substantial pressure on the Danish crown.
The loss of control
The control of the Sound was one of the principal sources of the League’s commercial dominance, and the control of the Sound was one of the principal causes of the wars between the League and the Danish crown. The control of the Sound was, however, gradually lost in the late fifteenth and early sixteenth centuries, as the Danish crown consolidated its authority and as the League’s military power declined. The control of the Sound was finally lost in 1658, when Sweden conquered Scania in the Treaty of Roskilde and the Danish Sound became, in effect, a free waterway.