An architectural dome is a rounded vault forming a roof or ceiling, usually hemispherical or elliptical in section and raised over a circular, square or polygonal space. Domes may be built of masonry, brick, timber, cast iron or concrete, and are often crowned by a lantern or pierced by an oculus to admit light.
The form was perfected by the Romans, most famously at the Pantheon, and passed into Byzantine, Islamic and Renaissance architecture. In Britain the great example is Sir Christopher Wren's St Paul's Cathedral, while smaller domes and cupolas crowned Palladian country houses, mausoleums, garden temples and stable blocks. Victorian and Edwardian architects used domes on town halls, banks, museums and conservatories, sometimes in glass and iron. Within the antiques trade the term also covers salvaged dome elements, timber and copper cupolas and glazed roof lanterns, which are sometimes reused in new buildings or garden structures. Interiors beneath a dome were frequently decorated with coffering, plasterwork or painted skies, and these details, together with the quality of the construction, help to date and assess surviving examples.
