When the Saljuqs began to dominate over the Abbasid Khalifah (on the downfall of Buwayids) a fresh impetus was given to the pursuit of astronomical studies. Jalal Uddin Malik Shah summoned at his new observatory at Rayy, Abur-Fath Omar Ibni-Ibrahim Al-Khayyami (1038 - 1123/24 AD) to reform the Persian calender. Khayyam was one of the most foremost mathematicians of the Middle Ages (in addition to being a poet of undying fame through his quatrains). His algebra gives an admirable classification of equations of the second and third degrees. Both analytical and geometrical solutions were explained for the second degree and attempted and partially solved for the third degree. He noted 13 different types of cubic equations and arranged them in the order of their complexity depending on the number of terms involved. (The modern method of classification of equations based on the term of the highest degree in the unknown quantity was introduced only in the sixteenth and seventeenth centuries). Imaginary roots were of course, not considered, negative roots too were ignored.

Ulugh Beg’s (d: 1449 AD) interpretation of Khayyam’s calender puts in about 3770 years. Modern interpretation introduces eight intercalary days in 33 years and leads to an error of one day in about 5000 years. We may add that the Gregorian correction in vogue at present in all civilized countries leads to an error of one day in 3330 days.

Khayyam worked on the determination of specific gravities also.

At the court of Sultan Sanjar flourished Abdul-Rahman Al-Mansur Al-Khazini (about 1115-1121 AD), a Greek (Rumi) slave whom is master Ali Al-Khazin provided with a good allround scientific education work on the balance, Mizanul-Hikmah, published recently with notes, etc, by the Da’iratul Ma’arif of Hyderabad.

Turning now to other mental disciplines of the Arabs, historiography, economics, geography, chemistry, botany, philosophy, etc, it is obvious that only their barest outlines can be sketched in this short paper. The Arabs had a natural liking for history and took endless pains to collect historical data and test their accuracy by certain standards that worked all right when applied to their own sources. Most of the earlier works were practically statements of events in their chronological sequence but expressed in an elegant style and above all with fair and often impartial criticism. Abul-Hasan Ali -Al-Masudi (956 AD) was the first to revolutionize the art of writing history. The modern method of dealing with different dynasties or countries or people with critical examination of the matter handled may be traced to the same writer.

In the front rank of Muslim histories are reckoned Ibn-Ishaq’s (d: 767 AD) “Biography of the Prophet” that has reached us only through a revision by Ibni-Hishaam (d: 834 AD), Musa Ibni-Uqbah’s (d: 758 AD) “Kitabul-Maghazi”, also Al-Waqidi’s (d: 823 AD) work on the same object and Ibni-Saa’d’s (d: 845 AD) “Siyar”, Abdul-Hakam’s (d: 870 AD) ‘Futuhul-Misr-wa-Akhbaruha” and Ahmad Ibni-Yahya Al-Baladhuri’s (d: 893 AD), “Futuhul-Buldan” describe Muslim conquests. The latter’s “Ansabul-Ashraf” deals with the lineages and pedigrees of persons of distinction. Amongst other writers of history may be mentioned Ibni-Muqaffa (d: 757 AD) who translated from Persian into Arabic a history of the Kings of Persia (hence the name “Siyar-i-Mulukil-Ajam”, Ibni-Al-Qutaybah), Muhammad Ibni-Muslim Al-Dinawari (d: 889 AD) author of “Kitabul-Ma’arif’, Ibni-Da’ud al-Dinawari (d: 895 AD) author of “Akhbar Al-Tiwal”, Hamzah Al-Isfahani (d: 961 AD) and Ibni-Wadih Al-Ya’qubi author of “Kitabul-Buldan” and Miskawayh (d: 1030 AD), author of a universal history “Tajaribul-Umam” from the earliest times down to about 980 AD.

The greatest historian of his century was Abu-Jafar Muhammad Ibni-Jarir Al-Tabari (838-923 AD) whose monumental work “Akhbar-i-Rusul wal-Muluk” is a mine of detailed and accurate information. Al-Tabari travelled in Iran, Iraq, Syria and Egypt to gather material for his book from original sources, and according to the geographer Yaqut, wrote 40 pages daily for 40 years. Later writers have made free use of this authoritative work. Ibni Al-Athir’s (1160-1234 AD) “Al- Kamil fi-Al-Tarikh” is an abridged edition of Al-Tabari’s older worked continued from where it stopped down to 1231 AD. A more original work by Ibni-Al-Athir is “Usud-Al-Ghabab”, a collection of some 7,500 biographies of the Companions of the Prophet (sws). We may mention here Sibt Ibni-Al-Jawzi’s (1186-1257 AD) universal history from creation to 1256 AD, called “Mir’at Al-Zaman fi Tarikh-Al-Ayyam”.

Reference had already been made to the improved system adoped by Al-Mas’udi in writing history. He travelled far and wide in practically every Islamic country in Asia from Baghdad and even went to Zanibar. Setting down finally (in the last decade of his life) in Egypt and Syria, compiling a work of 30 volumes. Only an abridged edition of it entitled “Muruj Al-Dhahab wa-Ma’adin Al-Jawahir”, brought down to 947 AD has survived. It is not confined to purely chronological facts but gives interesting geographical information as well, besides discussing, wherever appropriate, subjects of non-history and incipient notions (in vogue at the time) on evolution viz, successive gradation between inanimate mineral matter, plants animal and man, in “Al-Tanbih wal-Ishraf”.

Even after the fall of Baghdad there is no scarcity of historians in Islam. They flourished in the petty states that rose on the ruins of the Abbasid Caliphate. Among this category we find Abu Al-Fida (1272-1331 AD), author of “Mukhtasar Tarikh Al-Bashar” (an epitome of Ibni-Al-Athir,s “Al-Kamil fi Al-Tarikh” continued up to his own times), himself of princely rank (a lineal descendant of a bother of Salahuddin) and Governor of Hamah; Al-Dhahabi (1274-1348 AD) author of “Duwalul-Islam”; Abu Al-Mahasin Ibni-Taghri Birdi (1411-69 AD), attached to the court of Mamluk Sultans and author of “Al-Nujum Al-Zahirah fi Muluk Misr-wal-Qahirah” and Jalal Uddin Al-Suyuti (1445-1505 AD) author of 560 works on theology, history and philology of which we may mention “Husn Al- Muhadarah fi Akhbar Misr wal-Qahirah”, “Al-Muzhir fi’Ulum Al-Lughah” and “Al-Itqan fi Ulumil Qur’an”.

Arab writers excelled equally well in compiling biographies of notable persons. Ibni-Al-Asakir’s (d: 1177 AD) “Al-Tarikh Al-Kabir”, comprising 80 volumes, is devoted to the lives of great men of Damascus. Yaqut Ibni-Abdullah Al-Hamawi (1179-1229 AD) wrote “Mu’jam al-Udaba”, a charming biography of literati. Ali Ibni-Yusuf Al-Qifti (1172-1248 AD) author of “Ikhbar Al-Ulama bi-Akhbar Al-Hukama”, though a Wazir to Ayyubid rulers found time to compile biographies of physicians and philosophers; Muwaffaq Uddin Abu Al-Abbas Ahmad Ibni Abi-Usaybi’ah (1203-70 AD) himself a physician of Cairo, botanized with the Spanish scientist Ibni Al-Baytar and compiled a most comprehensive biography of some 400 notable physicians and surgeons (Greek and Arab) in his celebrated work “Uyun Al-Anba fi Tabaqat al-Atibba”, an inexhaustible source of information concerning the lives of Arab scientists in general, as the majority of them were not only physicians but astronomers, mathematicians and philosophers as well.

We close this sketchy list with the name of Shams Uddin Ahmad Ibni-Muhammad Ibni-Khallikan (1211-1282 AD), Qadi of Syria and author of a most delightful dictionary of national biography “Wafayatul-A’yan wa-Anba’ Al-Zaman”, dealing with the lives of 868 prominent Muslims---a marvel of accuracy and elegance.