Diwan al-Barid was established since the time of Caliph Umar al-Khattab. It was founded to be the office of postal system. But, in the Abbasid period, its official tasks were later been improved. Diwan al-Barid was led by an officer entitled Sahib al-Barid. This diwan managed all the matters involving the moving of letters, correspondence or any imperial orders across the world. In the Abbasid period, it was also used as the medium of spying and giving information for the caliphate.
|Using horses to pass the mails|