From the thirteenth to the seventeenth centuries, Kalmar was one of Sweden's most important cities. Between 1602 and 1913 it was the episcopal see of Kalmar Diocese, with a bishop, and the Kalmar Cathedral from 1702 is an example of classicistic architecture. It became a fortified city, with the Kalmar Castle as the center. After the Treaty of Roskilde in 1658, Kalmar's importance diminished, until the industry sector was initiated in the 19th century. The city is home to parts of Linnaeus University.