 Their enormous dimensions remained unsurpassed until the introduction of structural steel frames in the late 19th century (see List of the world's largest domes).Roman architecture supplied the basic vocabulary of Pre-Romanesque and Romanesque architecture, and spread across Christian Europe well beyond the old frontiers of the empire, to Ireland and Scandinavia for example.In the East, Byzantine architecture developed new styles of churches, but most other buildings remained very close to Late Roman forms.