Mathematician:Abu Rayhan Muhammad ibn Ahmad Al-Biruni

Mathematician
Khwarazmi scholar and polymath.

Thoroughly documented the Indian calendar with relation to the various Islamic calendars of his day.

Appears to be the first to have defined a second (of time) as being $\dfrac 1 {24 \times 60 \times 60}$ of a day.

Nationality
Khwarazmi

History

 * Born: 15 September 973 in Kath, Khwarazm (now Kara-Kalpakskaya, Uzbekistan)
 * Died: 13 December 1048 in Ghazna (now Ghazni, Afganistan)

Publications

 * تحقيق ما للهند من مقولة معقولة في العقل أو مرذولة (Kitab al-Hind; Kitab al-Bīrūnī fī Taḥqīq mā li-al-Hind, "A Critical Study of What India Says, Whether Accepted by Reason or Refused")
 * كتاب التفهيم لأوائل صناعة التنجيم (Kitab al-tafhim li-awa’il sina‘at al-tanjim, "Book of Instruction in the Elements of the Art of Astrology")
 * الآثار الباقية عن القرون الخالية ("The Remaining Signs of Past Centuries") (a treatise on calendars)
 * قانون مسعودي ("The Mas'udi Law")
 * التفهيم لصناعة التنجيم ("Understanding Astrology")
 * Pharmacy
 * الجماهر في معرفة الجواهر ("Gems")
 * Astrolabe
 * A Short History
 * History of Mahmud of Ghazni and his father
 * History of Khawarezm
 * Kitab al-Āthār al-Bāqīyah ‘an al-Qurūn al-Khālīyah ("The Chronology of Ancient Nations")
 * Risālah li-al-Bīrūnī ("Epître de Berūnī")

Also known as
In Persian:
 * ابوریحان محمد بن احمد البیرونی‎ (Abū Rayḥān Bērōnī)

New Persian:
 * Abū Rayḥān Bīrūnī


 * Known as
 * Biruni (Persian: بیرونی‎)
 * Al-Biruni (Arabic: البيروني‎)