Completed in 1897 to a design by William Byrne, it was conceived as a Roman Catholic cathedral for the Diocese of Clonfert, but what sets it apart from dozens of other late Victorian churches is what accumulated inside it over the following decades: a sustained and deliberate programme of arts and crafts decoration that made it, by the mid-twentieth century, one of the most remarkable interiors in Ireland.

The impetus came largely from Edward Martyn, a Galway landowner, playwright, and co-founder of the Irish Literary Theatre, who was instrumental in commissioning work from artists associated with the Celtic Revival. From around 1903 onwards, the cathedral became a kind of living gallery for that movement. Stained glass was supplied by An Túr Gloine, the cooperative studio founded in Dublin in 1903, and the windows made there by artists including Sarah Purser, Michael Healy, Evie Hone, and Hubert McGoldrick span nearly half a century of Irish glass-making. Healy alone contributed over twenty windows, and tracing the development of his style across them, from the cooler early work to the luminous intensity of his later panels, is like reading a private artistic biography. The cathedral also contains embroideries, sculpture, and metalwork produced by figures connected to the broader revival, giving the whole interior an unusual coherence of intent even across many years and many hands.

The building sits near the centre of Loughrea town, and the interior is generally accessible during daylight hours. The windows are best seen on a bright morning when light enters from the south and east, bringing out the particular quality of the glass that made An Túr Gloine work so distinctive, its depth of colour and its rejection of the mechanical flatness common in commercial Victorian glazing.