Question: When did the person who first brought a postal service into Umayyad lands become caliph?

Knowledge 1: Umayyad Caliphate
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. [SEP] Knowledge 2: Mu'awiya ibn Hisham
Mu'awiya ibn Hisham () was an Arab general, the son of the Umayyad Caliph Hisham ibn Abd al-Malik (r. 723–743), who distinguished himself in the Arab–Byzantine Wars. His son, Abd al-Rahman ibn Mu'awiya, was the founder of the Emirate of Córdoba and the Umayyad line of al-Andalus.
Knowledge 1: Umayyad Caliphate
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. [SEP] Knowledge 2: Umayyad Caliphate
Most historians[who?] consider Caliph Muawiyah (661–80) to have been the second ruler of the Umayyad dynasty, even though he was the first to assert the Umayyads' right to rule on a dynastic principle. It was really the caliphate of Uthman Ibn Affan (644–656), a member of Umayyad clan himself, that witnessed the revival and then the ascendancy of the Umayyad clan to the corridors of power. Uthman placed some of the trusted members of his clan at prominent and strong positions throughout the state. Most notable was the appointment of Marwan ibn al-Hakam, Uthman's first cousin, as his top advisor, which created a stir among the Hashimite companions of Muhammad, as Marwan along with his father Al-Hakam ibn Abi al-'As had been permanently exiled from Medina by Muhammad during his lifetime. Uthman also appointed as governor of Kufa his half-brother, Walid ibn Uqba, who was accused by Hashmites of leading prayer while under the influence of alcohol. Uthman also consolidated Muawiyah's governorship of Syria by granting him control over a larger area and appointed his foster brother Abdullah ibn Saad as the Governor of Egypt. However, since Uthman never named an heir, he cannot be considered the founder of a dynasty.
Knowledge 1: Umayyad Caliphate
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. [SEP] Knowledge 2: Punjab, Pakistan
The Punjabis followed a diverse plethora of faiths, mainly comprising Hinduism[citation needed] , when the Muslim Umayyad army led by Muhammad bin Qasim conquered Sindh and Southern Punjab in 712, by defeating Raja Dahir. The Umayyad Caliphate was the second Islamic caliphate established after the death of Muhammad. It was ruled by the Umayyad dynasty, whose name derives from Umayya ibn Abd Shams, the great-grandfather of the first Umayyad caliph. Although the Umayyad family originally came from the city of Mecca, their capital was Damascus. Muhammad bin Qasim was the first to bring message of Islam to the population of Punjab.[citation needed] Punjab was part of different Muslim Empires consisting of Afghans and Turkic peoples in co-operation with local Punjabi tribes and others.[citation needed] In the 11th century, during the reign of Mahmud of Ghazni, the province became an important centre with Lahore as its second capital[citation needed] of the Ghaznavid Empire based out of Afghanistan. The Punjab region became predominantly Muslim due to missionary Sufi saints whose dargahs dot the landscape of Punjab region.

Answer: 661