Stained glass windows
Stained glass windows were commonly used in churches for decorative and informative purposes. Stained glass, as an art form, reached its height in the Middle Ages when it became a major pictorial form and was used to illustrate the narratives of the Bible to a largely illiterate populace. Window glass was in use from at least the 1st century AD, and colored and painted window glass for use in religious buildings was also manufactured at an early date. The earliest extant example of ecclesiastical stained glass is possibly that from San Vitale in Ravenna, Italy. A clear glass roundel with a depiction of Christ in Majesty, thought to be 6th century, was discovered here.
The Cathedral Basilica of Saint Denis, a large medieval abbey church in the city of Saint-Denis, now a northern suburb of Paris. The building is of unique importance historically and architecturally, as its choir completed in 1144 is considered to be the first medieval Gothic architecture ever built.
Turku Cathedral – the Mother Church of the Evangelical Lutheran Church of Finland. It is the central church of the Archdiocese of Turku, regarded as one of the major records of Finnish architectural history.