Hoping for a rapid and victorious end of the Danish-Holstein-Hanseatic War, the Hanseatic league planned the seizure of the Danish capital and the destruction of the joint Danish-Swedish fleet in the harbour.

While King Eric left Copenhagen and prayed for the victory in Sorø Abbey, Queen Philippa managed the defence of the capital.

Under massive shelling from Danish land-based artillery, armed bridges, and floating batteries the Hanseatic ships failed to blockade the harbour and to surround the Danish-Swedish fleet.

With the help of these floating batteries the Hanseats were able to extend the range of their artillery and to cover the Danish and Swedish ships with a massive bombardment.

Already in the end of July 1428 at least seven ships were repaired and won a naval battle against the Victual Brothers who were allied with the Hanseatic League and Holstein.