Taht-i-revan

Mavi Boncuk |
A Sedan chair, revived at the Turkish Village of the World's Columbian Exposition, 1893.

Portuguese and Spanish navigators and colonists encountered litters of various sorts in India, Mexico, and Peru. They were imported into Spain and spread into France and then England. All the names for these devices derived from the root "sed-" from the Latin "sella" - the traditional name for a carried chair. The simplest litter, often called a stretcher, consists of a sling attached along its length to poles or stretched inside a frame. The poles or frame are carried by porters in front and behind. Such simple litters are common on battlefields and emergency situations, where terrain prohibits wheeled vehicles from carrying away the dead and wounded.
Another form, commonly called a sedan chair, consists of a chair or windowed cabin suitable for a single occupant, also carried by at least two porters in front and behind, using wooden rails that pass through brackets on the sides of the chair. These porters were known in London as "chairmen". These have been very rare since the 19th century, but such enclosed portable litters have been used as an elite form of transport for centuries, especially in cultures where women are kept secluded.