The Category A listed Holy Trinity is the most historic church in St Andrews. The church was initially built on land, close to the south-east gable of the Cathedral, around 1144, and was dedicated in 1234 by Bishop David de Bernham. It then moved to a new site on the north side of South Street between 1410–1412 by bishop Warlock. Much of the architecture feature of the church was lost in the re-building by Robert Balfour between 1798–1800. The church was later restored to a (more elaborately decorated) approximation of its medieval appearance between 1907–1909 by MacGregor Chambers.
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.