The barīd was the official system of swift overland communication employed by Muslim rulers throughout much of premodern Islamic history. The English term "postal system" refers to the fact that people and riding-mounts were posted at convenient intervals along a route, in order to allow couriers to rest and obtain new mounts for the next leg of their journey. The original meaning of the Arabic term barīd is unclear. In early Arabic texts, the word could be used with numerous meanings, including postal mount, courier, way-station, the distance