The town supported the deposed king Christian II of Denmark (1525),
and opposed the Reformation in Denmark (1535), and in both cases found
itself among the defeated. The Reformist King Christian III of Denmark
abstained however from retaliation, and instead founded a castle to
protect the harbour. The castle, built where the monastery had been
situated until the Reformation, was completed by 1560.

The city of Landskrona was founded at the location of Scania's (at
that time a part of Denmark) best natural harbour, as a means of King
Eric of Pomerania's anti-Hanseatic policy, intended to compete with
Danish towns under Hanseatic control. A Carmelite monastery was
founded in 1410, English merchants were granted the privileges in a
royal charter in 1412, and the town itself was chartered in
1413. Landskrona was burned by the Hanseatic League in 1428.  

Any further plans for Landskrona were however not realized, for
various reasons. The continued Swedish-Danish wars favoured
Karlskrona, located at a safer distance from Denmark, replacing
Landskrona as a naval base, the fortifications were discontinued, and
Malmo remained the most important commercial town - despite Malmo
lacking a harbour until the late 18th century. The fortifications at
Landskrona were expanded considerably between 1747 and 1788, but were
condemned in 1822, whereafter the garrison was abolished in 1869. The
walls and moats of the fortifications are today a beautiful
recreational area, commonly known as the Landskrona Citadel.

When Scania had been ceded to Sweden in 1658, the good harbour and the
strong fort were reasons for plans to make Landskrona a commercial
center of the acquired territory with extraordinary privileges for
foreign trade. The castle was reinforced by bastions, the area inside
the moats extended to 400x400 meters, the castle was considered the
strongest and most modern in Scandinavia, but was temporarily lost to
the Danes after a comparably short siege July 8-August 2, 1676. The
commandant Colonel Hieronymus Lindeberg was consequently sentenced to
death for high treason.
