This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: Mu'awiyah introduced postal service, Abd al-Malik extended it throughout his empire, and Walid made full use of it. The Umayyad Caliph Abd al-Malik developed a regular postal service. Umar bin Abdul-Aziz developed it further by building caravanserais at stages along the Khurasan highway. Relays of horses were used for the conveyance of dispatches between the caliph and his agents and officials posted in the provinces. The main highways were divided into stages of 12 miles (19 km) each and each stage had horses, donkeys or camels ready to carry the post. Primarily the service met the needs of Government officials, but travellers and their important dispatches were also benefitted by the system. The postal carriages were also used for the swift transport of troops. They were able to carry fifty to a hundred men at a time. Under Governor Yusuf bin Umar, the postal department of Iraq cost 4,000,000 dirhams a year.
A:
Who first brought a postal service into Umayyad lands?