The area surrounding Nafplio has been inhabited since ancient times, but few signs of this, aside from the walls of the Acronauplia, remain visible. Subsequently, Byzantines, Franks, Venetians, and Turks added to the fortifications. It became a place of considerable importance, and has continued so down to the present day. In the time of the Crusades it first emerges from obscurity. Nafplio was taken in 1212 by French Crusaders of the Principality of Achaea. It became part of the lordship of Argos and Nauplia, which in 1388 was sold to the Republic of Venice, who regarded it as one of their most important places in the Levant. During the subsequent 150 years, the lower city was expanded and fortified, and new fortifications added to Acronauplia.
Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.