BARĪD, the official postal and intelligence service of the early
Islamic caliphate and its successor states. The service operated
by means of couriers mounted on mules or horses or camels or
traveling on foot. In this way, official letters and dispatches
were delivered to the central dīvān in Damascus or Baghdad or
such provincial capitals as Shiraz, Bukhara, and Ḡazna; and,
since this was an official institution, with its personnel
drawing their salaries from the central or provincial
exchequers, it was only exceptionally that private
correspondence was carried. The use of such a communications
network dates back in the Iranian world to the Achaemenids, with
their relay service along the “Royal Roads” such as the one from
Sardis to Susa (cf. Herodotus, 5.52-3; Camb. Hist. Iran II/I,
pp. 276-77), and was perpetuated by the Sasanians. Hence Ḵᵛāja
Neẓām-al-Molk was correct (Sīar al-molūk [Sīāsat-nāma], chap.
10, ed. Darke1, Tehran, 2535 = 1353 Š./1974, p. 79, tr. Darke,
The Book of Government, London, 1960, p.