It was made a religiously and politically influential city through its association with the moon-god Sin; many prominent Mesopotamian rulers consulted with and renovated the moon-temple of Ekhulkhul in Harran.

The Harranian moon cult of Sin proved to be enduring and lasted long into the Middle Ages, known to have existed as late as the 11th century AD.

Harran transitioned back into a semi-permanent village settlement in the 1840s, but has only recently grown into a permanent town through advancements in local irrigation and agriculture.

[18][19] Due to the prominence of both Harran and Carrhae in historical literary sources, some scholars use the compound name "Carrhae-Harran" for the ancient city.

[26] Although next to nothing is known of the architecture and layout of Harran prior to the Middle Ages,[27] the city is believed to have been designed according to a vaguely moon-shaped plan[10] since Medieval sources allude to this.

[21] In the following century the Amorite king Shamshi-Adad I (r. 1808–1776 BC) is recorded to have launched an expedition to conquer the region around Harran and secure the trade routes there from hostile forces.

[41] From the first century BC until the end of antiquity, Harran was typically located near or on the border of the Roman (later Byzantine) and Parthian (later Sasanian) empires.

[18][46] Harran, along with the nearby cities of Nisibis and Hatra, were captured by the Sasanian king Ardashir I in 238–240 but was swiftly retaken by Emperor Gordian III.

[41] Despite its paganism, Harran was a site of interest to Christians since the city is mentioned in the Book of Genesis as the town where Abraham and his family stopped on their way from Ur of the Chaldees to Canaan.

[34] The last pagan Roman emperor, Julian (r. 361–363) intentionally avoided the Christian Edessa[20][41] and instead stopped at Harran in 363 to consult the oracles of the moon temple on his upcoming Persian campaign.

[4] Later sources indicate that the deities worshipped by the pagans of Harran in late antiquity included Sin, Bat-Nikkal (consort of Sin; a different name from his ancient consort Ningal),[44] the "lord with his dogs" (identified as a localised version of the god Nergal), Tar'atha (identified with the Syrian goddess Atargatis), Gadlat (an Arabian goddess), and perhaps Shamash.

[51] When the armies of the Rashidun Caliphate, led by the general Iyad ibn Ghanm, besieged Harran in the winter of 639–640 it was the pagans of the city who negotiated its peaceful surrender.

[8][53] The reason for Marwan moving his court to Harran is not known,[54] but might be either to better monitor the troublesome eastern provinces of the caliphate[10] or due to the anti-Christian sentiment of the city's pagan population,[55] who had never been disloyal to the Umayyads.

Some adopted syncretistic faiths tolerable by the Muslims, others continued to honor the old deities of ancient Mesopotamia and Syria, and some primarily worshipped the stars and planets.

[60] In 830, Harun al-Rashid's son Al-Ma'mun (r. 813–833) arrived at Harran with an army on his way to raid in the Byzantine Empire[34] and intended to destroy the city due to its large pagan population.

The precise date when this happened and the events surrounding it are unknown, perhaps coinciding with the city falling under the control of the Fatimid Caliphate[63] in 1038 through the submission of the Numayrid ruler Shabīb ibn Waththāb,[64] or more likely with a failed anti-Uqaylid rebellion in 1083.

It was then under the control of various Turkish princes; first Jikirmish of Mosul (1102–1106), then the Artuqids of Mardin (1106–1127) and then the Zengid dynasty, which captured Harran under Imad al-Din Zengi in 1127.

[68] The Mongols are also variously stated to either have simply walled up the gates but otherwise left what remained intact[4] or to have pillaged the city for building materials before burning down the remnants.

[4] Under the Ottoman Empire, which captured the region in the early 16th century, Harran was the capital of a nahiyah (a local administrative unit composed of a group of villages).

[8] One of the major semi-nomadic tribes that have continuously lived in and around Harran since the Middle Ages and still today are the Nmēr,[i] descendants of the medieval Numayrid lords of the city.

[68] By the middle of the 20th century, Harran comprised about a hundred houses, inhabited by semi-settled nomadic Arabs, most of whom still did not stay at the site for the duration of the entire year.

[8] Particularly important in this development was the Turkish Southeastern Anatolia Project, launched in the 1970s, which through irrigation efforts transformed the formerly dry desert plains surrounding Harran into productive agricultural fields.

It was probably initially a palace but was converted into a more castle-like militaristic building in the 11–13th centuries when the region surrounding Harran experienced considerable political turmoil.

[6] Another important historical monument in Harran is its ancient burial mound, spread over a large area and partially surviving intact at the center of the city's archaeological site.

[91] Since wood is rare in the region around Harran owing to its climate, locals have traditionally built houses from materials they could easily gather such as stone, brick and mud.

The beehive houses were compatible with the nomadic lifestyle of the locals since they can be built and dismantled rapidly, like a tent, but also efficiently resist both heat and cold.

This feature, combined with the thick walls, provide relatively good indoor conditions throughout the year, even in the extreme summer heat.

[8] The ancient ruins at Harran function like an open-air museum[78] and the town is a popular local tourist attraction,[83] often visited as a day trip from Urfa.

[112] Although Harran was of great interest to historians due to its association with the ancient moon cult and its abundant appearances in Mesopotamian, Roman and Arab historical writings, the site itself did not receive significant archaeological attention until the 19th century owing to its geographical remoteness.

[4] In 2012 and 2013, the Şanlıurfa Museum Directorate, with Mehmet Önal acting as consultant, carried out more extensive excavations at Harran, focusing on the walls, burial mound and castle.