Abu al-Tayyib Sanad ibn Ali, also known as Sind ibn Ali (died c. 864 C.E.), was a ninth-century

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

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 ''trans ...

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, mathematical structure, structure, space, Mathematica ...

and

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

during

Islamic Golden Age The Islamic Golden Age was a period of scientific, economic, and cultural flourishing in the history of Islam, traditionally dated from the 8th century to the 13th century. This period is traditionally understood to have begun during the reign o ...

who was employed at the court of the

Abbasid The Abbasid Caliphate or Abbasid Empire (; ) was the third caliphate to succeed the prophets and messengers in Islam, Islamic prophet Muhammad. It was founded by a dynasty descended from Muhammad's uncle, Abbas ibn Abd al-Muttalib (566–653 C ...

caliph

Al-Ma'mun Abū al-ʿAbbās Abd Allāh ibn Hārūn al-Maʾmūn (; 14 September 786 – 9 August 833), better known by his regnal name al-Ma'mun (), was the seventh Abbasid caliph, who reigned from 813 until his death in 833. His leadership was marked by t ...

. A later convert to

Islam Islam is an Abrahamic religions, Abrahamic monotheistic religion based on the Quran, and the teachings of Muhammad. Adherents of Islam are called Muslims, who are estimated to number Islam by country, 2 billion worldwide and are the world ...

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

Baghdad Baghdad ( or ; , ) is the capital and List of largest cities of Iraq, largest city of Iraq, located along the Tigris in the central part of the country. With a population exceeding 7 million, it ranks among the List of largest cities in the A ...

Biography

Sanad ibn Ali was either an

Iraqi Jewish The history of the Jews in Iraq (, ', ; , ) is documented from the time of the Babylonian captivity . Iraqi Jews constitute one of the world's oldest and most historically significant Jewish communities. The Jewish community in Mesopotamia, kn ...

or a Sindhi from

Mansura Mansoura (; ' , rural: ) is a city in Egypt located on the eastern bank of the Damietta branch of the Nile river. The city is the capital of the Dakahlia Governorate and has a population of 621,953 as of 2021. Etymology ''Mansoura'' in Arabic ...

, capital of

Arab Sind Sind (, Urdu & ) was an administrative division of the Umayyad Caliphate and later of the Abbasid Caliphate in History of India, post-classical India, from around 711 CE with the Umayyad conquest of Sindh by the Arabs, Arab military commander Mu ...

. He is known to have translated and modified the

Zij al-Sindhind ''Zīj as-Sindhind'' (, ''Zīj as‐Sindhind al‐kabīr'', lit. "Great astronomical tables of the Sindhind"; from Sanskrit ''siddhānta'', "system" or "treatise") is a work of zij (astronomical handbook with tables used to calculate celestial pos ...

. The Zij al-Sindhind was the first astronomical table ever introduced in the

Muslim World The terms Islamic world and Muslim 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, politics, and laws of Islam or to societies in which Islam is ...

. As a mathematician Sanad ibn ʿAlī was a colleague of

al-Khwarizmi Muhammad ibn Musa al-Khwarizmi , or simply al-Khwarizmi, was a mathematician active during the Islamic Golden Age, who produced Arabic-language works in mathematics, astronomy, and geography. Around 820, he worked at the House of Wisdom in B ...

and worked closely with

Yaqūb ibn Tāriq Yaʿqūb ibn Ṭāriq (; referred to by some sources as Yaʿqūb; died ) was a Persian astronomer and mathematician who lived in Baghdad. Career Yaʿqūb ibn Ṭāriq was active in Baghdad as an astronomer during the rule of the second Abbasi ...

together they calculated the

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

of the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

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 FIle:Decimal separators.svg, alt=Four types of separating decimals: a) 1,234.56. b) 1.234,56. c) 1'234,56. d) ١٬٢٣٤٫٥٦., Both a comma and a full stop (or period) are generally accepted decimal separators for international use. The apost ...

notation to the

Arabic numerals The ten Arabic numerals (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) are the most commonly used symbols for writing numbers. The term often also implies a positional notation number with a decimal base, in particular when contrasted with Roman numera ...

was introduced by Sanad ibn Ali. According to

Ibn Abi Usaibia Ibn Abī Uṣaybiʿa Muʾaffaq al-Dīn Abū al-ʿAbbās Aḥmad Ibn Al-Qāsim Ibn Khalīfa al-Khazrajī (‎; 1203–1270), commonly referred to as Ibn Abi Usaibia (also ''Usaibi'ah, Usaybea, Usaibi`a, Usaybiʿah'', etc.), was a physician from S ...

: the Banū Mūsā 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 Ja'far ibn al-Mu'tasim, Muḥammad ibn Harun al-Rashid, Hārūn al-Mutawakkil ʿalā Allāh (); March 82211 December 861, commonly known by his laqab, regnal name al-Mutawwakil ala Allah (), was the tenth Abbasid Caliphate, Abbasid caliph, rul ...

at his new capital

Samarra Samarra (, ') is a city in Iraq. It stands on the east bank of the Tigris in the Saladin Governorate, north of Baghdad. The modern city of Samarra was founded in 836 by the Abbasid caliph al-Mu'tasim as a new administrative capital and mi ...

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 () is an Arabic male given name common in most parts of the Muslim world. Other English spellings of the name include Ahmed. It is also used as a surname. Etymology The word derives from the root ( ḥ-m-d), from the Arabic (), from ...

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 ...

instead to

Al-Farghani Abū al-ʿAbbās Aḥmad ibn Muḥammad ibn Kathīr al-Farghānī () also known as Alfraganus in the West (870), was an astronomer in the Abbasid court in Baghdad, and one of the most famous astronomers in the 9th century. Al-Farghani composed ...

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 Banū Mūsā 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 Mathematicians from the Abbasid Caliphate Engineers of the medieval Islamic world Year of death unknown 9th-century people from the Abbasid Caliphate Year of birth unknown 9th-century translators Converts to Islam from Judaism Jews from the Abbasid Caliphate 9th-century astronomers 9th-century Jews from the Abbasid Caliphate