Kalmar

In 1397 Queen Margaret gathered the rulers of Denmark, Norway and Sweden at Kalmar, and on 13 July the union that bore the town's name was sealed; it held, with many breaks, until 1523. Kalmar went on paying for its place on the frontier. In 1599 the castle garrison, loyal to King Sigismund, surrendered to Duke Charles, who had its three commanders and nineteen others executed. The Danish siege that opened the Kalmar War in 1611 wrecked much of the medieval town, and in 1640 the Council of the Realm ordered it moved onto the island of Kvarnholmen, where a new fortified town was finished by 1658. That same year the Treaty of Roskilde pushed the frontier south, and when Karlskrona became the navy's main base in 1689, Kalmar ceased to be Sweden's southern bastion.