Abu al-Tayyib Sanad ibn Ali al-Yahudi (died c. 864 C.E.), was a ninth-century Iraqi Jewish

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

translator Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transl ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

and

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considerin ...

employed at the court of the

Abbasid The Abbasid Caliphate ( or ; ar, الْخِلَافَةُ الْعَبَّاسِيَّة, ') was the third caliphate to succeed the Islamic prophet Muhammad. It was founded by a dynasty descended from Muhammad's uncle, Abbas ibn Abdul-Mutta ...

caliph

Al-Ma'mun Abu al-Abbas Abdallah ibn Harun al-Rashid ( ar, أبو العباس عبد الله بن هارون الرشيد, Abū al-ʿAbbās ʿAbd Allāh ibn Hārūn ar-Rashīd; 14 September 786 – 9 August 833), better known by his regnal name Al-Ma'm ...

. A later convert to

Islam Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the ...

, Sanad's father was a learned Jewish astronomer who lived and worked in

Baghdad Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon ...

Biography

He is known to have translated and modified the Zij al-Sindhind. The Zij al-Sindhind was the first astronomical table ever introduced in the

Muslim World The terms Muslim world and Islamic world commonly refer to the Islamic community, which is also known as the Ummah. This consists of all those who adhere to the religious beliefs and laws of Islam or to societies in which Islam is practiced. I ...

. As a mathematician Sanad ibn ʿAlī was a colleague of

al-Khwarizmi Muḥammad ibn Mūsā al-Khwārizmī ( ar, محمد بن موسى الخوارزمي, Muḥammad ibn Musā al-Khwārazmi; ), or al-Khwarizmi, was a Persian polymath from Khwarazm, who produced vastly influential works in mathematics, astronom ...

and worked closely with Yaqūb ibn Tāriq together they calculated the

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid f ...

of the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

and other astronomical bodies. He also wrote a commentary on '' Kitāb al-ğabr wa-l-muqābala'' and helped prove the works of

. The decimal point notation to the

Arabic numerals Arabic numerals are the ten numerical digits: , , , , , , , , and . They are the most commonly used symbols to write decimal numbers. They are also used for writing numbers in other systems such as octal, and for writing identifiers such a ...

was introduced by Sanad ibn Ali. According to Ibn Abi Usaibia: the

Banū Mūsā The Banū Mūsā brothers ("Sons of Moses"), namely Abū Jaʿfar, Muḥammad ibn Mūsā ibn Shākir (before 803 – February 873); Abū al‐Qāsim, Aḥmad ibn Mūsā ibn Shākir (d. 9th century); and Al-Ḥasan ibn Mūsā ibn Shākir (d. 9th ce ...

brothers out of sheer professional jealousy kept him away from

Abbasid Caliph The Abbasid caliphs were the holders of the Islamic title of caliph who were members of the Abbasid dynasty, a branch of the Quraysh tribe descended from the uncle of the Islamic prophet Muhammad, Al-Abbas ibn Abd al-Muttalib. The family came ...

al-Mutawakkil Abū al-Faḍl Jaʿfar ibn Muḥammad al-Muʿtaṣim bi-ʾllāh ( ar, جعفر بن محمد المعتصم بالله; March 822 – 11 December 861), better known by his regnal name Al-Mutawakkil ʿalā Allāh (, "He who relies on God") was ...

at his new capital

Samarra Samarra ( ar, سَامَرَّاء, ') is a city in Iraq. It stands on the east bank of the Tigris in the Saladin Governorate, north of Baghdad. The city of Samarra was founded by Abbasid Caliph Al-Mutasim for his Turkish professional ar ...

and had caused Sanad ibn ʿAlī to be sent away to

. Both Ja'far Muhammad ibn Mūsā ibn Shākir and

Ahmad ibn Mūsā ibn Shākir Ahmad ( ar, أحمد, ʾAḥmad) is an Arabic male given name common in most parts of the Muslim world. Other spellings of the name include Ahmed and Ahmet. Etymology The word derives from the root (ḥ-m-d), from the Arabic (), from the v ...

delegated the work of digging a great

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface f ...

instead to

Al-Farghani Abū al-ʿAbbās Aḥmad ibn Muḥammad ibn Kathīr al-Farghānī ( ar, أبو العبّاس أحمد بن محمد بن كثير الفرغاني 798/800/805–870), also known as Alfraganus in the West, was an astronomer in the Abbasid court ...

and thus ignoring Sanad ibn ʿAlī, the better engineer.

committed a great error, making the beginning of the canal deeper than the rest and water never reached the new garrison of ''Al-Ja'fariya''. News of this greatly angered

and the two

brothers were saved from severe punishment only by the gracious willingness of Sanad ibn ʿAlī, to vouch the corrections of

's calculations thus risking his own welfare and possibly his life.

References

{{DEFAULTSORT:Ibn Ali, Sind Astronomers from the Abbasid Caliphate Astronomers of the medieval Islamic world Mathematicians from the Abbasid Caliphate Medieval engineers Year of death unknown 9th-century people from the Abbasid Caliphate Year of birth unknown 9th-century translators Converts to Islam from Judaism 9th-century Jews Jews from the Abbasid Caliphate