Gulf of Danzig

The Gulf of Danzig formed the sea approach to Gdańsk and the mouth of the Vistula. During the Polish–Swedish war of 1626–1629, access to its port became a military objective. Swedish warships imposed a blockade and demanded heavy customs payments from merchant captains. Gdańsk's council and King Sigismund III responded by developing a royal fleet capable of challenging them.

On 28 November 1627 ten Polish ships met a Swedish squadron of six in the gulf, in the battle remembered as Oliwa. The Polish fleet captured the Swedish flagship Tigern, while Solen exploded during the fighting. Both the Polish commander Arend Dickmann and the Swedish admiral Nils Stiernsköld died. Victory temporarily lifted the blockade, but Swedish restrictions returned the following spring. The engagement demonstrated the vulnerability of commercial navigation to naval power. It also showed the limits of a single success: the war in Prussia continued, and the port's freedom of movement still depended on wider military and diplomatic events.