Old St Peter's Church is a ruined parish church in Thurso. It dates to at least 1125, and at one time was the principal church for the county, administered by the Bishops of Caithness.
Early in the 16th century, the vicarage of Thorso was held by Sir John Mathesoun chancellor of Caithness, on whose demission or otherwise Queen Mary in 1547 presented Master John Craig to the benefice. Master Walter Innes, who appears in record in 1554, was vicar of Thurso in 1560, and continued to hold the vicarage between 1561 and 1566. About 1567, John Rag was minister, and in 1574, Alexander Urquhart was minister of Olrik and Thurso, and John Davidsoun was reader at Thurso. In 1641, Alexander Monro, minister at Durnoch had from King Charles I, a grant of 800 marks Scots or of eight chalders victual in augmentation of his stipend from the rents of the bishopric in the parish of Thurso and elsewhere.
Old St Peter's, still standing, was disused since 1832 when a replacement church was built for the parish. That church, St Andrew's and St Peter's, is of Gothic style and was built to a design by William Burn.
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.