With the rule of the Sassanids, Persian kings who ruled Mesopotamia (Cyrus and Xerxes), it regained its central position along the trade routes, since under Roman and Hellenic rule they had lost. There are not many Sassanid records of this time. What is known to be a very rich culture, have you seen Omar Khayyam's “A Thousand and One Nights” tale.
After the Arab conquest, in 641 originated Baghdad, replacing Babylon, which had disappeared. The mathematics of the Islamic period reveals the same mix of influences that became familiar in Alexandria and India.
Mathematics and astronomy were greatly encouraged by the Caliphs of Baghdad: Al-mansur (754-775), Harun Al-raschid (766-809) and Al-mamun (813-833). The latter organized in Baghdad the “house of wisdom,” consisting of a library and an observatory.
Arab mathematical activities began with Al-Fazari's translation of the Hindu Siddanthas and culminated in Muhammad Ibn Musa Al-Khwarizmi around 825. He wrote several treatises on mathematics and astronomy. These treaties explained the Hindu numbering system. Europe got to know this numbering system thanks to a 12th century Latin copy, as the original Arabic was lost. Al-Khwarizmi's astronomy was a summary of the Siddanthas, which showed a Greek influence on Sanskrit texts.
It should be noted that the word “algebra” comes from the Arabic “al-jabr”, meaning “restoration”.
The Arabs played a very important role in the history of mathematics, as they faithfully translated the Greek classics (Apollonius, Archimedes, Euclid, Ptolemy, and others). These classics would be lost to us without the Arabs, given the closure of the Athens school by Justinian.
Another brilliant mathematician was Omar Khayyam. He wrote an algebra that contained a systematic investigation of cubic equations using the intersection of two conic sections.
Jemshid Al-Kashi, Persian mathematician solved cubic equations by iteration and trigonometric methods, and also by the method known today as the "Horner method". This method has a strong Chinese influence, which makes us think that the Chinese mathematics of the Sung Dynasty had penetrated deep into the Islamic world.
For all this, the important influence of the Arab people on mathematics is emphasized. It is also noteworthy that Muslims in expanding Islam committed one of the greatest crimes against humanity. After the fall of Alexandria against the Muslims, the caliph had all the manuscripts found in the library burned (about 600,000) arguing that: "if they are in the Quran they need not be kept and if they are not they are useless." Legend has it that the writings fed the bath boilers for six months.
One must also remember the role of the crusades. With the crusades Christian Europe had, again, contact with Greek mathematics, translated into Arabic. This came to greatly influence medieval Europe and served as a source for the development of mathematics during the Middle Ages.<