The Cathedral of the Immaculate Conception in Sligo was developed by Bishop Laurence Gillooly who had been appointed Bishop of Elphin in 1858. He decided that the diocese was now of a size and wealth that the time had come to replace St. John's Parish Chapel, which had been recognised as the diocesan pro-cathedral.
He engaged George Goldie, one of the foremost Catholic architects in England in the nineteenth century. The cathedral was opened for divine worship on 26 July 1874 by Cardinal Paul Cullen of Dublin.
Modelled on a Normano–Romano–Byzantine style, it is the only example of a Romanesque style cathedral built during the 19th century. Designed in the shape of a basilica, the church has a square, pyramid-capped tower, which reaches a height of 70 metres, and supporting turrets at the west end. The circular baptistery incorporated in the apse with its five lancet windows behind the high altar, was originally designed as a mortuary chapel.
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.