Situated on the eastern section of the walls, Porta Pretoria provided the main access to the city of Augusta Praetoria. It was built in 25 BC after the defeat of the Salassians by Terenzio Varrone. It had three openings, which are still visible today: the central one for carriages and the side openings for pedestrians. The area inside the openings was used as a troop parade court, in its southern section, the land was dug up as far as the level of the ground during the Roman era.
On the outer facing openings you can still see the grooves from where the gates were lowered at night. The eastern facade still has some of the marble slabs that once covered the entire monument, on the inside it consists of blocks of puddingstone. In the Middle Ages there was a chapel dedicated to the Most Blessed Trinity resting against Porta Praetoria (now only an alcove of this remains), for many centuries, the same Porta Praetoria went by its name.
References: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.