The Quran was originally revealed and written in Arabic language - at a time when the Arabic nation was illiterate as the Prophet (PBUH) said, “We are an unlettered nation, we do not write or calculate”.
Generally speaking most Arabs were illiterate and a few were familiar with writing. But indeed there were talented individuals who could write in Arabic and other calligraphies.
The Arabs of north Arabia, known as Nabataeans transferred calligraphy and Arabic writing to the Hijaz region - Mecca and Medina. Nabataeans, who were part of ancient Arabs, inhibited northern Arabia and Southern Levant and established their kingdom at the edge of Levant with its rock-cut capital city known as ”Sila’a” - currently known as Petra in the south of Jordan. They developed unique aspects of civilization and extended relations with Hira and Anbar cities in Iraq; due to the business and artistic relationships between Arabs of southern Iraq, and the tribes of northern Hejaz, such interchanges included the transfer of Nabataean’s calligraphies.
Since the prophet-hood era the art of writing flourished and spread amongst people. The prophet (PBUH) was keen to teach his companions the art of writing. He made an educational incentive to release each prisoner of Badre battle from Quraish young captives who could be entrusted with ten children to teach them the art of writing and reading. Ibn Abbas narrated: “some prisoners couldn’t afford to pay the ransom on Badre battle and the prophet (PBUH) released them ransomed for teaching Ansar the art of writing ”.
As to the writing of the Holy Quran during the lifetime of the Prophet (PBUH) it was made in the Hijazi Calligraphy which was prevalent at the time. This script was void of the letter discriminating dots and diacritical marks in accordance with the tools available in that era.
Muslims showed a great interest in the writing script and in transcribing copies of the Holy Quran. Many calligraphers became very skillful in this field; with some exceptional brilliant who produced elegant forms of script.
Arabic calligraphy continued to evolve progressively, until the beginning of the third Hijri century when calligraphy leadership rested in the hands of Minister Abi Ali Mohammad bin Ali bin Muqla (d. 328 A.H.) to whom the developed of the Arabic calligraphy attributed as he introduced a few improvements. As reported, he brought to six the types of Arabic calligraphy, namely, Thuluth, Naskh, Tawqi', Rayhani (named after basil stalks due to its overlapping letters), Muhaqqaq (a calligraphy used by book scribes) and Riqa' (similar to the Thuluth, and was used at the Office of Letters.
The people of Baghdad gave great interest to Arabic calligraphy and the umber scribes has reached around 500 calligraphers in Baghdad since the Abbasid era until the present time, which is believed to be a large number in one city. Therefore, contemporary calligrapher and poet, Walid Al-A'dhami, wrote a two-volume book under the title of "An Encyclopedia of Baghdadi Calligraphers" where he listed all Baghdadi characters involved in Arabic calligraphy.
The Moroccan type of calligraphy spread in North, West and Central Africa as well as in Andalusia (Spain). Apparently, this calligraphy emerged first at Kairouan, which was established in 50 A.H. The Moroccan calligraphy was developed from the Kufic calligraphy which was devoted to transcribing the Holy Quran in that region. This type of calligraphy is known as Kairouan calligraphy, in relation to the place of origin.
The Ottoman Empire gave much attention to calligraphies and there were many Ottoman and Turkish calligraphers. After the Abbasid Caliphate, the Ottoman Empire paid serious attention to the Arabic calligraphy and a group of Turkish calligraphers excelled in transcribing the Holy Quran.