|Bab Mardum Mosque, Toledo|
This short article is taken from the full article which is available here as a PDF file
The glory of Toledo in the 11th century was the development of exact sciences. Here can be found the mathematicians al-Waqqadi and al-Tugibi; the geometers Ibn al-Attar and Ibn Hamis who were also astronomers. Amongst these illustrious figures was Muhammad ibn Al-Safar, who in 1029 made an astrolabe which, centuries after, was found in the Sprenger collection. It was later transferred to the Staatsbibliothek of Berlin and can today be located in the Westdeutsche Bibliothek of Marburg (still in Germany). Here could be found Ibn al-Bagunis and Ibn Wafid and here could be seen the rising star of Muslim scholarship, the young al-Zarqali. Said Al-Andalusi (al-Tulaytuli) (of Toledo) (1029-1070) has left us important information on this subject in his Tabaqat al-Umam (The Classification of Nations) which has been studied by illustrious historians.
Ibrahim ibn Said Al-Wazzan (1085 C.E.) is known to have been a prominent instrument maker working in Valencia and Toledo. From 1085 onwards his son Muhammad worked with him. He made at least six astrolabes, one of which he constructed in Toledo in June 1067 and which centuries later became part of the collection of D. Faustino de Borbon before ending up in the Archaelogical Museum of Madrid (there is an electrotype of it in the London Science Museum). The following year, he made another astrolabe also in Toledo, which now is in the Lewis Evans Collection in the Museum of the History of Science, Oxford. His four other astrolabes are today scattered in different museums, mostly in Rome at the Museo Astronomico and the Museo Kircheriano. In 1085, with his son, he made a celestial globe with its stand (Kursi) for the Vizier Abu Issa B. Labbun (the minister at the Toledo court mentioned above). The globe was formerly in the Belluomini Collection, but is now in the Museo di storia della Scienza in Florence. Tracing the works of this remarkable instrument maker and giving him due credit through raising awareness of his achievements is highly necessary. There is a vast but widely scattered bibliography mainly in Spanish that can be researched through.
Toledo was the residence of a great number of able architects. Fath B. Ibrahim (Fl. 934; d. 1013) was known as al-Qashari, a scholar, pious man and architect who, although flourishing in the Caliph court of Cordova, was also credited for building two mosques in Toledo. He also restored the fortifications of Makkada and Waqqash. His contemporaries were the architects Musa. B. Ali, al-Banna (the constructor) and Saada, who erected the mosque of Bab Mardum known now as San Cristo de la Luz and is dated from the years 999-1000.
Al-Zarqali (Arzachel) (1029-1087) was a Spanish Muslim of a family of artisans who entered the services of Qadi Ibn Sa'id of Toledo as a maker of delicate instruments. He lived in Toledo until the city became insecure following Christian attacks.
Al-Zarqali prepared the famous Toledan Tables, the original version of which were in Arabic are lost but two Latin versions have survived. Ptolemy's exaggerated estimate of the length of the Mediterranean Sea at 62o were first cut by al-Khwarizmi to 52o then probably by al-Zarqali to the near the correct value of 42o. Al-Zarqali's work was translated into Latin by Gerard of Cremona and was very popular for more than two centuries. All subsequent tables for different locations in the Christian West were based on al-Zarqali's measurements such as the tables of Marseilles, and his tables were also adapted to the meridians of London, Paris and Pisa. Robert of Chester's work was less a translation than an adaptation of the tables of al-Battani and al-Zarqali for the coordinates of London, 1149.
Al-Zarqali was also a renowned instrument maker. As Barron Carra de Vaux tells us, he was given the surname `Al-Nekkach' which means the engraver of metals. According to established tradition he was a mechanic and metal craftsman who was very able with his hands. It was as an instrument maker that al-Zarqali entered the services of Qadi Ibn Said of Toledo. He was needed to make delicate instruments essential to continue astronomical observations begun in 1060, possibly by Yahia Ibn Abi Mansur. First Al-Zarqali built instruments for other scholars, but when they realised his great intellect, they became interested in him. As he told them that he was man of little learning, having never studied any science nor touched a book, they put him to task and made him study and learn, putting at his disposal the books he needed to educate himself. Two years later, in 1062, he became a member of the group and soon after its director. Al-Zarqali continued to make instruments requested by others but now began to invent his own and he also began to teach his own masters to the point that they soon began to follow his example. He invented and constructed an astrolabe - a safiha - about which he wrote a treatise out of which a whole literature developed. A Jew from Montpellier in France translated it into Latin; King Alfonso of Castile made two translations of it into Romance (Spanish) whilst Regiomontanus in the fifteenth century published a collection of problems on the `noble instrument of the safiha.' Around 1062 Al-Zarqali constructed the water clocks of Toledo, descriptions of which can be found in Al-Zuhri as conveyed to us in Spanish by Millas Vallicrosa and partly in English as in the following extract from Thomson:
The clocks consisted of two basins, which filled with water or emptied according to the increasing or waning of the moon. At the moment when the new moon appeared on the horizon, water would begin to flow into the basins by means of subterranean pipes, so that there would be at day-break the fourth of a seventh part, and at the end of the day half a seventh part, of the water required to fill the basins. In this proportion the water would continue to flow until seven days and as many nights of the month had elapsed, by which time both basins would be half filled. The same process during the following seven days and nights would make the two basins quite full, at the same time that the moon was at its full. However, on the fifteenth night of the month, when the moon would begin to wane, the basins would also begin to lose every day and night half a seventh part of their water, until by the twenty-first of the month they would be half empty, and when the moon reached her twenty-ninth night not a drop of water would remain in them. It is worthy of remark that, should anyone go to any of the basins when they were not filled, and poured water into them with a view to quicken its filling, the basins would immediately absorb the additional water and retain no more than the just quantity; and, on the contrary, were anyone to try, when they were nearly filled, to extract any or the whole of their water, the moment the hands are raised, the basins would pour out sufficient water to fill the vacuum in an instant
The clocks were in use until 1133 when Ibn Zabara was given permission by Alfonso VII (the new Christian ruler) to see how they worked but he failed to reassemble them after dismantling them. With Al-Zarqali now dead, details of his techniques were lost.