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.
The foundation was done at a place for a fishing settlement, historical described as Sønder Sæby ("sønder" means "southern"). Still today exists a very small settlement just north of the town, known as Säby (Sæby in Danish). This probably was the Nørre Sæby ("nørre" means "northern") in the beginning of the 15:th century, but since the southern village became the town, the need for distinguish northern and southern Sæby disappeared. The original name of the officially founded town was Landszkrone. But changed to Landskrone sometime before 1450.
The town supported the 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.