Mar 222014


Today is the birthday (1394) of Mīrzā Muhammad Tāraghay bin Shāhrukh (Chagatai: میرزا محمد طارق بن شاہ رخ, Persian: میرزا محمد تراغای بن شاہ رخ‎‎) better known as Ulugh Beg (الغ‌ بیگ) a ruler in the Timurid dynasty in Central Asia as well as an astronomer, mathematician and sultan. His commonly used name, Ulugh Beg, is not a personal name, but rather a nickname, which can be loosely translated as “Great Ruler” or “Patriarch Ruler” and was the Turkic equivalent of Timur’s Perso-Arabic title Amīr-e Kabīr. Ulugh Beg was also notable for his work in astronomy-related mathematics, such as trigonometry and spherical geometry. He built the great Ulugh Beg Observatory in Samarkand between 1424 and 1429. It was considered by scholars to have been one of the finest observatories in the Islamic world at the time and the largest in Central Asia. He built the Ulugh Beg Madrasah (1417–1420) in Samarkand and Bukhara, transforming the cities into cultural centers of learning in Central Asia. He was also a mathematics genius of the 15th century — albeit his mental aptitude was perseverance rather than any unusual endowment of intellect. His observatory is situated in Samarkand which is in Uzbekistan.


He ruled Uzbekistan, Tajikistan, Turkmenistan, Kyrgyzstan, southern Kazakhstan and most of Afghanistan for almost half a century from 1411 to 1449. He was a grandson of the great conqueror, Timur (Tamerlane) (1336–1405), and the oldest son of Shah Rukh, both of whom came from the Turkic Barlas ethnic group of Transoxiana (now Uzbekistan). His mother was a noblewoman named Goharshad, from the Turkic aristocracy of Giyasitdin Tarhan. Ulugh Beg was born in Sultaniyeh in Persia during Timur’s invasion. As a child he traveled through a substantial part of the Middle East and India as his grandfather expanded his conquests in those areas. After Timur’s death, however, and the accession of Ulugh Beg’s father to much of the Timurid Empire, he settled in Samarkand, which had been Timur’s capital. After Shah Rukh moved the capital to Herat (in modern Afghanistan), sixteen-year-old Ulugh Beg became his governor in Samarkand in 1409. In 1411, he became the sovereign ruler of the whole Mavarannahr khanate.


The teenaged ruler set out to turn the city into an intellectual center for the empire. Between 1417 and 1420, he built a madrasah (“university” or “institute”) on Registan Square in Samarkand (currently in Uzbekistan), and he invited numerous Islamic astronomers and mathematicians to study there. The madrasah building still survives. Ulugh Beg’s most famous pupil in astronomy was Ali Qushchi (died in 1474). He was also famous in the fields of medicine and poetry. He used to debate with other poets, regarding a range of contemporary issues. He liked to debate in a poetic style, called “Bahribayt” among local poets.

Ulugh Beg proposed that a mixture of alcohol with garlic, could help treat conditions like diarrhea, headache, stomach ache, and intestinal illnesses. He also offered advice for newly married couples, suggesting recipes containing nuts, dried apricot, dried grape etc. were useful in increasing a man’s virility. Fortunately his astronomy and mathematics were stronger than his medical skills.


His own particular interests concentrated on astronomy, and, in 1428, he built an enormous observatory, called the Gurkhani Zij, similar to Tycho Brahe’s later Uraniborg as well as Taqi al-Din’s observatory in Istanbul. Lacking telescopes to work with, he increased his accuracy by increasing the length of his sextant; the so-called Fakhri sextant had a radius of about 36 meters (118 feet) and the optical separability of 180″ (seconds of arc).

Using it, he compiled the 1437 Zij-i-Sultani of 994 stars, generally considered the greatest star catalog between those of Ptolemy and Brahe, a work that stands alongside Abd al-Rahman al-Sufi’s Book of Fixed Stars. The serious errors which he found in previous Arabian star catalogs (many of which had simply updated Ptolemy’s work, adding the effect of precession to the longitudes) induced him to redetermine the positions of 992 fixed stars, to which he added 27 stars from Abd al-Rahman al-Sufi’s catalog  Book of Fixed Stars from the year 964, which were too far south for observation from Samarkand. This catalog, one of the most significant of the Middle Ages, was first edited by Thomas Hyde at Oxford in 1665 under the title Tabulae longitudinis et latitudinis stellarum fixarum ex observatione Ulugbeighi and reprinted in 1767 by G. Sharpe. More recent editions are those by Francis Baily in 1843 in vol. xiii of the Memoirs of the Royal Astronomical Society and by Edward Ball Knobel in Ulugh Beg’s Catalogue of Stars, Revised from all Persian Manuscripts Existing in Great Britain, with a Vocabulary of Persian and Arabic Words (1917).

In 1437, Ulugh Beg determined the length of the sidereal year as 365.2570370…d = 365d 6h 10m 8s (an error of +58 seconds). For his measurements he used a 50 m high gnomon (shadow casting rod as on a sundial). This value was improved by 28 seconds in 1525 by Nicolaus Copernicus, who appealed to the estimation of Thabit ibn Qurra (826–901), which had an error of +2 seconds. However, Beg later measured another more precise value as 365d 5h 49m 15s, which has an error of +25 seconds, making it more accurate than Copernicus’ estimate which had an error of +30 seconds. Beg also determined the Earth’s axial tilt as 23.52 degrees, which remained the most accurate measurement for hundreds of years. It was more accurate than later measurements by Copernicus and Tycho Brahe.

In mathematics, Ulugh Beg wrote accurate trigonometric tables of sine and tangent values correct to at least eight decimal places. The trigonometric results include tables of sines and tangents given at 1° intervals. These tables display a high degree of accuracy, being correct to at least 8 decimal places. The calculation is built on an accurate determination of sin 1° which Ulugh Beg solved by showing it to be the solution of a cubic equation which he then solved by numerical methods. He obtained:

sin 1° = 0.017452406437283571

The correct approximation is:

sin 1° = 0.017452406437283512820

which shows the remarkable accuracy which Ulugh Beg achieved. Not a brilliant mathematician, but a dogged one.

Ulugh Beg’s scientific expertise was not matched by his skills in leadership. When he heard of the death of his father Shahrukh Mirza, Ulugh Beg went to Balkh, where he heard that his nephew Ala-ud-Daulah Mirza bin Baysonqor, son of Ulugh’s brother Baysonqor, had claimed the emirship of the Timurid Empire in Herat. Consequently Ulugh Beg marched against his nephew and met him in battle at Murghab. Having won this battle, Ulugh Beg advanced toward Herat and massacred its people in 1448. But Ala-ud-Daulah’s brother Mirza Abul-Qasim Babur bin Baysonqor came to his aid, defeating Ulugh Beg. Ulugh Beg retreated to Balkh, where he found that its governor, his oldest son Abdal-Latif Mirza, had rebelled against him. Another civil war ensued.


Within two years, he was beheaded by the order of his own eldest son while on his way to Mecca. Eventually, his reputation was rehabilitated by his nephew, Abdallah Mirza (1450–1451), who placed Ulugh Beg’s remains in the mausoleum of Timur in Samarkand, where they were found by archeologists in 1941. It was discovered that Ulugh Beg had been buried in his clothes which is known to indicate that he was considered a martyr. The injuries inflicted on him were evident when his body was examined :

… the third cervical vertebra was severed by a sharp instrument in such a way that the main portion of the body and an arc of that vertebra were cut cleanly; the blow, struck from the left, also cut through the right corner of the lower jaw and its lower edge.

Here is a classic soup from Yazd, now in Iran but in the Timurid Empire when Ulugh Beg ruled.  It is quite complex in flavor, but not awfully difficult to make.  The dill and beets are a common taste of the region.  The dumplings and yoghurt are essential for me to cut the richness of the soup.

© Shoorba-ye Yazdi (Lentil and Beet Soup with Pasta Dumplings)

Slice a medium onion and sauté in a little oil until golden.


Add ½ teaspoon of turmeric and sauté for a minute or two more.


Put the onions in a soup pot with 1 cup of lentils and 1 cup of diced beet.


Add 5 cups of chicken stock, bring to a boil and simmer until the lentils are soft (1 to 2 hours).


Add ½ cup of chopped greens (beet tops if available, otherwise chard or spinach) . . .


. . . and a handful of chopped dill.  Continue to simmer while you make the dumplings.


Place ½ cup of flour in a bowl.


Slowly add water until you have a soft dough.


Knead on a floured board for 5 minutes.


Tear into flat disks.


Add the dumplings to the soup and cook for 8 to 10 minutes, or until al dente.


Add 2 tablespoons of vinegar.


Serve hot in a deep bowl with a dollop of plain yoghurt or sour cream. It can also be served cold.