Muqas (stalactite vault) is a distinctive structural and configurational feature of Islamic architecture.It is used to provide a transition from a square plan to a circular perimeter,thus allowing a domical or semi-domical space to be erected above a square or rectangular layout.It is similar to the Roman pendentive in its structural logic but quite different in form and architectonic detail.The use of muqas has become ubiquitous in Islamic architecture and was applied structurally and decoratively above major spaces in mosques and mausoleums,wall niches,facades,arches,friezes,and entrance portals.This paper provides a historical,typological,and stylistic analysis of Bahri Mamluk muqas portals developed in Cairo,Egypt during the 13th and 14th centuries.Due to the complexity and breadth of this undertaking,the current study focuses on the earliest 10 monuments that exemplify the type and examines the origin,meaning,and development of muqas portals in Egypt.Local and foreign influences are analyzed with an eye on identifying similarities and variations in terms of constructability,geometry,and complexity of muqas configurations.The paper concludes with a discussion of the primary innovative features of Bahri Mamluk Muqas and their effect on subsequent muqas development in Egypt.