Royal-imperial church architecture is crowning the historic city centre. The cathedral is definitely not to be missed on any sightseeing trip round Graz. Don’t be fooled by the relatively restrained exterior. The "Gottesplagenbild", an inspiring relic of splendid Gothic fresco painting, is still in excellent condition today. Inside the cathedral, a multitude of ecclesiastical along with general historical treasures is waiting to be discovered.
Today's cathedral reminds of the days when Graz was an imperial city. Emperor Frederick III erected the church together with his new residence in Graz. In the course of history, the cathedral saw many changes. Construction work of the court and parish church in late-Gothic style was started in 1438, as Jesuit church it was refurbished in Baroque style in the late 17th and early 18th centuries. Since 1786 it has been the cathedral, i.e. the bishop's and main church of the Catholics in Styria.
The exterior of the cathedral looks very sober today. In the Gothic period, however, the façades were covered with paintings. One fresco has been preserved - the so-called Gottesplagenbild ("God's Plagues").
https://www.graztourismus.at/en/see-and-do/sightseeing/sights/cathedral_sh-1241