St Mary's Old Church parish church in the Church of England located in Old Town on St Mary's, Isles of Scilly. It was built at Old Town, Isles of Scilly during the 12th century, perhaps around 1130. Re-building was carried out between 1660 and 1667 including the addition of the south aisle, and a west end gallery for soldiers from the Garrison. Further improvements were made in 1743 when the east end was rebuilt.
By the nineteenth century, it was derelict and under the orders of Augustus Smith, Lord Proprietor of the Islands, it was restored.
The churchyard of Old Town church serves as the principal cemetery for the island of St Mary's. Over the centuries countless members of the old Scilly families have been buried here, as have been the crews of numerous ships lost near the Isles. Among them are Sir John Narborough and his brother James, the sons of Rear Admiral Sir John Narborough, who both died in the sinking of HMS Association in 1707. Also buried here is Ann Cargill (1760–1784), an 18th-century opera diva and celebrated beauty of her time. She died when her ship sank off the Western Rocks and was first buried on Rosevear, before eventually being interred at Old Town Church.
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.