St Magnus Cathedral dominates Kirkwall, the main town of Orkney. Originally Roman Catholic, it is the oldest cathedral in Scotland and the most northerly cathedral in the United Kingdom. Today, it is a parish church of the Church of Scotland. The cathedral is a fine example of Romanesque architecture built when the Orkney Islands were ruled by the Norse Earls of Orkney. The cathedral is named after Saint Magnus Erlendsson who was Earl of Orkney from c. 1106 to about 1117.

The construction of the Romanesque cathedral begun in 1137 and has examples of Norman architecture, attributed to English masons who may have worked on Durham Cathedral. The masonry uses red sandstone quarried near Kirkwall and yellow sandstone from the island of Eday. In the late 12th and early 13th century, the building was extended to the east, and, in the late 14th century, the present lower front was joined to the rest of the building. These later elements introduced the Gothic style with pointed arches.