The Qur’an was revealed to Prophet Muhammad (ﷺ) in the Arabic language and the companions wrote it down as per the direction of the Prophet (ﷺ), in the authentic classical Fusha Arabic language. At the time, Fusha was not written with diacritical marks or vowel notations or signs, it was just the letters that were written down. The Qur’an was written by the companions on tanned skins, large sections of bone, and on tree barks and leaves. It (The Qur’an) was not in one book or form, rather it was spread out in the homes of different companions, and it was not gathered together in one person’s home during the time of the Prophet (ﷺ).
During the reign of AbuBakr As-Siddeeq (May Allah be pleased with him), and after the wars of Riddah where in a lot of people who had memorized the Qur’an were martyred, Umar (May Allah be pleased with him) suggested to AbuBakr that they compile and gather the different parts of the Qur’an that were spread amongst the companions into one book and in one location.
A group of companions took on this noble task and Zaid bin Thabit (May Allah be pleased with him) was appointed as their leader. The Qur’an was compiled and gathered in the order we have it today into one form/book and it was kept in the house of AbuBakr. After the death of AbuBakr, the collection was then kept in Umar’s house (May Allah be pleased with him), then after his death, it was kept with his daughter; Hafsah bint Umar (May Allah be pleased with her).
The Collection remained with Hafsah (in her home) until Uthman (May Allah be pleased with him) became the Khalifah of the Muslims. There were many situations where people differed regarding the recitations and the different dialects of the Arabs at the time. Due to these issues, Uthman ordered that the Mushaf be compiled and verified in one book only. From this one copy that was compiled and verified, more copies were made and sent to different parts of the Muslim world at the time as a reference for the people in those regions. This compilation was referred to as The Mushaf Al-Imam and its script was unifying in that it encompassed all the dialects and variations of the Arabic language at the time. This script was referred to as Rasm Al-Uthmaani (رسم العثماني) commonly known as the Uthmaniy Script till date.
As Islam spread far and wide, there was significant increase in the number of people who were accepting Islam from non-Arab parts of the world. The languages spoken by Muslims was no longer just Arabic in its pure form, foreign languages were increasingly common and due to this influx of non-Arab Muslims that could not read and understand Arabic nor the Qur’an in its pre-diacritical marks form, the need to identify the letters with marks and dots arose. Likewise, the need to add vowel signs also became important. Abu Al-Aswad Ad-Dualiy (May Allah have mercy on him) took on the responsibility of completing the I’rab (إعراب) of the Qur’an and adding marks to the Qur’an during the caliphate of the Umawiyyoon. The marks were written in different colors at the time and to represent a fatha, he put a colored dot on top of the letter, and for a Kesra, a colored dot on the bottom of the letter, and for a dammah, a colored dot next to the letter, and for tanween (التنوين), there were two dots side by side. These dots were referred to as the dots of I’rab.
During the Abbasid Caliphate many improvements and changes were made to the script of the Qur’an. Al Khaleel bin Ahmad Al-Basriy introduced the vowel signs that we know today as Fathah(ﹷ), Kesra(ﹻ), Dammah(ﹹ) and Tanween to the Uthmaniy script. He also added to it the Shaddah (ﹽ), the sign of Idhhaar, the Madd signs, and the signs of Imaalah and Ishmaam [these are specific terms in the science of Tajweed that allow for the initial integration of the different recitation styles that the Qur’an was revealed in, all included in the original Uthmaniy script of the Qur’an].
As for the dots that are present on some letters to distinguish them from other similarly shaped letters (like ب, ت, ث and ج, ح, خ), it is generally accepted that they were introduced to the script of the Qur’an by Nasir Ad-Deen bin ‘Asim and Yahyaa bin Y’amir. They added these dots during the caliphate of the Umawiyoon and these dots were referred to as The Dots of the Foreigners. They were named as such to help the foreigners avoid reading/ reciting the Qur’an incorrectly due to their lack of knowledge of the Arabic language.
The Noble Mushaf was not partitioned into juz(جزء), hizb(حزب), and rub’(ربع) as we have it today. They only used to put three dots at the ends of every verse (ayah), and after every five verses, they would write the word ‘five (خمس)’. After every ten verses, they would write the word ‘ten (عشر)’. And whenever both words were written together, it meant it was the 15th verse, and this was the format until the end of the surah (chapter). It was later that they began writing the numbers of the verses with figures at the end of every verse, until the end of the surah.
During the Abbasid era, the Mushaf was divided into 30 parts, and each Juz was divided into two hizbs, and each hizb further divided into four rub’. This is the partitioning and division we have today in the Mushaf. It should be made clear that this partitioning is just for ease and it is not required to be enforced in any way shape or form.