Tinboeth Castle is believed to have been built by Roger Mortimer during the 13th century. Following Mortimer's death, the castle fell into ruin and little of the structure remains. The castle was constructed in an Iron Age hillfort and measures around 100 metres in diameter. The Royal Commission on the Ancient and Historical Monuments of Wales notes that the remains indicate the site featured a twin-towered gatehouse on the north-east corner of the structure.
The outer bailey of the castle utilised the hillfort as a defence, while the inner bailey featured a stone wall which was accessed by the gatehouse.
An earthwork remains, believed to be the remains of a wall, but little stonework above ground except the collapsed remains of the gatehouse.
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.