Islamic leaders, their biographies and accomplishments. Saul Silas Fathi

to Donald Routledge Hill, al-Jazari described the most sophisticated candle clocks known to date. Hill described one of al-Jazari’s candle clocks as follows:

      The candle, whose rate of burning was known, bore against the underside of the cap, and its wick passed through the hole. Wax collected in the indentation and could be removed periodically so that it did not interfere with steady burning. The bottom of the candle rested in a shallow dish that had a ring on its side connected through pulleys to a counterweight. As the candle burned away, the weight pushed it upward at a constant speed. The automata were operated from the dish at the bottom of the candle. No other candle clocks of this sophistication are known.

      Al-Jazari’s candle clock also included a dial to display the time and, for the first time, employed a bayonet fitting, a fastening mechanism still used in modern times.

       Elephant clock:

      The elephant clock was described by al-Jazari in 1206 is notable for several innovations. It was the first clock in which an automaton reacted after certain intervals of time (in this case, a humanoid robot striking the cymbal and a mechanical robotic bird chirping) and the first water clock to accurately record the passage of the temporal hours to match the uneven length of days throughout the year.

       Castle clock:

      Al-Jazari’s largest astronomical clock was the “castle clock”, which was a complex device that was about 11 feet (3.4 m) high, and had multiple functions besides timekeeping. It included a display of the zodiac and the solar and lunar orbits, and an innovative feature of the device was a pointer in the shape of the crescent moon which travelled across the top of a gateway, moved by a hidden cart, and caused automatic doors to open, each revealing a mannequin, every hour. Another innovative feature was the ability to re-program the length of day and night in order to account for their changes throughout the year. Another feature of the device was five automaton musicians who automatically play music when moved by levers operated by a hidden camshaft attached to a water wheel. Other components of the castle clock included a main reservoir with a float, a float chamber and flow regulator, plate and valve trough, two pulleys, crescent disc displaying the zodiac, and two falcon automata dropping balls into vases.

       Weight-driven water clocks:

      Al-Jazari invented water clocks that were driven by both water and weights. These included geared clocks and a portable water-powered scribe clock, which were a meter high and half a meter wide. The scribe with his pen was synonymous to the hour hand of a modern clock. al-Jazari’s famous water-powered scribe clock was reconstructed successfully at the Science Museum (London) in 1976.

       Miniature paintings:

      Alongside his accomplishments as an inventor and engineer, al-Jazari was also an accomplished artist. In The Book of Knowledge of Ingenious Mechanical Devices, he gave instructions of his inventions and illustrated them using miniature paintings, a medieval style of Islamic art.

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Al-Khursani, Abu Muslim Abd Rahman ibn Muslim (700-755): Or al-Khurasani AKA Behzādān pour Vandād Hormozd was an Abbasid general of Persian origin, who led the first major and organized liberal movement against the Umayyad dynasty.

       Life and Origin:

      His original name was Behzadan, prior to his father Vandad Hurmoz’s conversion to Islam, who adopted the name of ‘Moslem’ for himself. His birthplace remains obscure, though the oldest historical reference, the 11th century Al-Mahasin al-Isfahan written by Mafzal Ibn-Sa’d Maforukhi Esfahani, claims he was born in the town of Fereidan in the central Iranian province of Isfahan. It is also claimed he was born in the village of Sanjerd or Makhowan near the city of Merv in what is now Turkmenistan.

       Crushing a Shiite rebellion in Bukhara:

      There was an Arab by the name Sharik ibn Shaikh al-Mahri in Bukhara, who wanted to spread Shi’a Islam firmly and oppose anyone against him. Soon, he got the support of several local rulers and many local people.

      When this news reached Abu Muslim (Khurasani), he along Ziyad ibn Salih came there to find out what the details, and soon they got involved in a fight. Abu Muslim fought Sharik ibn Shaikh al-Mahri and his Shiite supporters for thirty-seven days with no victory, everyday Abu Muslim’s side was losing soldiers and several taken as prisoners. After that, all of a sudden Sharikh ibn Shaikh (Shiite leader) died, and his supporters started to crumble & fear, but they were still hostile. The rebellion was eventually crushed and most of the Shi’a supporters were hanged.

       Rise and revolution:

      Abu Muslim was a major supporter of the Abbasid cause, having met with their Imam Ibrahim ibn Muhammad in Mecca, and was later a personal friend of Abu al-’Abbas Al-Saffah, the future Caliph. He observed the revolt in Kufa in 736 tacitly. With the death of the Umayyad Caliph Hisham ibn Abd al-Malik in 743, the Islamic world was launched into civil war. Abu Muslim was sent to Khorasan by the Abbasids initially as a propagandist and then to revolt on their behalf. He took Merv in December 747 (or January 748), defeating the Umayyad governor Nasr ibn Sayyar, as well as Shayban al-Khariji, a Kharijite aspirant to the caliphate. He became the de facto Abbasid governor of Khorasan, and gained fame as a general in the late 740s in defeating the peasant rebellion of Bihafarid, the leader of a syncretic Persian sect that were Mazdaism. Abu Muslim received support in suppressing the rebellion both from purist Muslims and Zoroastrians. In 750, Abu Muslim became leader of the Abbasid army and defeated the Umayyads at Battle of the Zab. Abu Muslim stormed Damascus, the capital of the Umayyad caliphate, later that year.

      His heroic role in the revolution and military skill, along with his conciliatory politics toward Shi’a, Sunnis, Zoroastrians, Jews, and Christians, made him extremely popular among the people. Although it appears that Abu al-’Abbas trusted him in general, he was wary of his power, limiting his entourage to 500 men upon his arrival to Iraq on his way to Hajj in 754. Abu al-’Abbas’ brother, al-Mansur (r. 754-775), advised al-Saffah on more than one occasion to have Abu Muslim killed, fearing his rising influence and popularity. It seems that this dislike was mutual, with Abu Muslim aspiring to more power and looking down in disdain on al-Mansur, feeling al-Mansur owed Abu Muslim for his position. When the new caliph’s uncle, Abdullah ibn Ali rebelled, Abu Muslim was requested by al-Mansur to crush this rebellion, which he did, and Abdullah was given to his nephew as a prisoner. Abdullah was ultimately executed.

      Relations deteriorated quickly when al-Mansur sent an agent to inventory the spoils of war, and then appointed Abu Muslim governor of Syria and Egypt, outside his powerbase. After an increasingly acrimonious correspondence between Abu Muslim and al-Mansur, Abu Muslim feared he was going to be killed if he appeared in the presence of the Caliph. He later changed his mind and decided to appear in his presence due to a combination of perceived disobedience, al-Mansur’s promise to keep him as governor of Khorasan, and the assurances of some of his close aides, some of whom were bribed by al-Mansur. He went to Iraq to meet with al-Mansur in Madain in 755. Al-Mansur proceeded to enumerate his grievances against Abu Muslim, who kept reminding the Caliph of his efforts to enthrone him. Against al-Muslim were also charges of being a Zendic or heretic. Al-Mansur then signaled five of his guards behind a portico to kill him. Abu Muslim’s mutilated body was thrown in the river Tigris, and his commanders were bribed to acquiesce to the murder.

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Al-Khwarizmi (780-847): The origin of all the physical sciences can, one way or another, be traced back to mathematics. According to the historians, archaeological excavations carried out in the Nile Valley and Mesopotamia have shown that counting was familiar to both ancient Egyptians and the Babylonians. The Chinese and Indians also devised their own distinctive ways of counting, just as the Arabs used the positions of their fingers to help them count during the time of the Prophet Muhammad.

      Though the zero-based number system was known to the ancient Indians, it was the Muslims who invented the word ‘zero’. Derived from the