Semi-dome

[1] Small semi-domes have been often decorated in a shell shape from ancient times,[2] as in Piero della Francesca's Throned Madonna with saints and Federigo da Montefeltro,[3] and the example in the gallery below.

Islamic examples may use muqarnas decorative corbelling, while in Late Antique, Byzantine and medieval church architecture the semi-dome is the classic location for a focal mosaic, or later fresco.

In buildings like Hagia Sophia in Byzantine architecture, apsidal openings or exhedras from the central nave appear in several directions, not just to the liturgical east.

When the Byzantine styles were adapted in Ottoman architecture, which was even less concerned with maintaining a central axis, a multiplicity of domes and semi-domes becomes the dominating feature of both the internal space and the external appearance of the building.

In Western Europe the external appearance of a semi-dome is less often exploited than in Byzantine and Ottoman architecture, and is often disguised as a sloping rather than curved semi-circular roof.