Egyptian Revival architecture in the British Isles is a survey of motifs derived from Ancient Egyptian sources occurring as an architectural style. Egyptian Revival architecture is comparatively rare in the British Isles. Obelisks start appearing in the 17th century, mainly as decorative features on buildings and by the 18th century they started to be used in some numbers as funerary or commemorative monuments. In the later 18th century, mausoleums started to be built based on pyramids, and sphinxes were used as decorative features associated with monuments or mounted on gate piers. The pylon, a doorway feature with spreading jambs which support a lintel, also started to be used and became popular with architects.