In July 1361, King Valdemar IV of Denmark invaded Gotland and defeated local forces near Visby. Control over Gotland and the trading town of Visby mattered because it affected Baltic Sea commerce and access to key routes. This move helped trigger a wider struggle between Denmark and Hanseatic cities over trade privileges and maritime power.
On 8 July 1362, a Hanseatic-led fleet fought Denmark near Helsingborg during the first phase of the Danish–Hanseatic conflict. The Danish victory weakened Hanseatic leverage at sea and pushed the League toward negotiating from a less favorable position. It also showed that control of the Øresund strait was central to both war and trade.
On 22 November 1365, Denmark and leading Hanseatic cities concluded the (first) Peace of Vordingborg. The settlement reflected the League’s weakened position after naval losses, and it did not secure the full set of privileges the cities wanted. Dissatisfaction with this outcome helped set the stage for a renewed, more organized Hanseatic effort against Denmark.
On 19 November 1367, Hanseatic cities and several Dutch towns formed the Confederation of Cologne to coordinate war aims, funding, and naval support against Denmark. This alliance marked a shift from mostly commercial cooperation toward organized military action to protect trading rights. The confederation helped the League return to war with greater capacity and unity.
From 4 April to 16 June 1368, Hanseatic and allied forces besieged Copenhagen, looted the city, and destroyed Absalon’s Castle. The attack directly targeted Denmark’s ability to control the Øresund and collect revenues tied to shipping and trade. It increased pressure on Denmark to accept a settlement restoring Hanseatic commercial advantages.
On 24 May 1370, Denmark and the Hanseatic League signed the Treaty of Stralsund, ending the war of 1361–1370. The treaty restored and expanded Hanseatic trading rights and strengthened the League’s influence over Baltic commerce. It is often treated as a high-water mark for Hanseatic political and economic leverage over Denmark.
In 1426, a new war began between the Hanseatic League and the Kalmar Union (dominated by Denmark) during the reign of Eric of Pomerania. A key issue was control of shipping routes and tolls in the Øresund, which affected who profited from Baltic trade. The conflict again tied commercial policy to naval warfare and alliances in northern Europe.
Between 6 April and 15 June 1428, Hanseatic fleets attacked Copenhagen twice during the Dano–Hanseatic War. The successful bombardment demonstrated how maritime firepower could disrupt a capital city and its trade administration. It also signaled that the League was willing to strike Denmark directly to protect commercial interests.
In mid-July 1435, the Peace of Vordingborg ended the Dano–Hanseatic War and confirmed important Hanseatic privileges, especially connected to northern trade. The settlement weakened King Eric’s political position and contributed to a broader crisis in the Kalmar Union. The outcome showed how trade rights and control of sea routes could shape dynastic politics.
On 8–9 November 1520, King Christian II oversaw mass executions in Stockholm after his victory in Sweden. The event helped drive Swedish resistance and increased reliance on outside support, including the Hanseatic city of Lübeck. This crisis in Scandinavian politics affected northern trade by changing who controlled ports and toll points around the Baltic.
In 1523, Christian II was deposed in Denmark, ending his reign and opening a new phase of instability in Scandinavian power politics. This mattered to the Hanseatic League because shifts in Danish leadership could change trade policy, toll enforcement, and relations with German merchant cities. The political uncertainty contributed to later conflict in which Lübeck tried to shape Denmark’s future.
From May 1534 to 29 July 1536, Denmark fought the Count’s Feud, a succession struggle that became a wider northern conflict. Lübeck and other Hanseatic interests backed one side, aiming to protect or expand trade privileges in Denmark. The war’s outcome reduced Lübeck’s influence and marked a turning point toward stronger state control over trade and foreign policy.
Hanseatic–Danish wars and northern conflicts (1361–1523)