Rabbi Zag de Sujurmenza was a
Jewish convert of 13th-century Spain who helped King
Alfonso X of Castile
Alfonso X (also known as the Wise, es, el Sabio; 23 November 1221 – 4 April 1284) was King of Castile, León and Galicia from 30 May 1252 until his death in 1284. During the election of 1257, a dissident faction chose him to be king of Germ ...
with his scientific works.
Zag de Sujurmenza was commissioned by the king to write ''Astrolabio redondo'' (spherical
astrolabe
An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستارهیاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...
), ''Astrolabio llano'' (flat astrolabe), Constelaciones (constellations) and ''Lámina Universal'' (an instrument that improved on the astrolabe); he also translated the book ''Armellas de
Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
'', and wrote about the ''Piedra de la sombra'' (stone of the shadow, or sundial), ''Relox de agua'' (clepsydra, or
water clock
A water clock or clepsydra (; ; ) is a timepiece by which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel, and where the amount is then measured.
Water clocks are one of the oldest time-m ...
) ''Argente vivo o azogue'' (quicksilver or mercury) and ''Candela'' (candle clock). Of his works, the most important are those of the "round astrolabe" and the "flat astrolabe". In the first, the author rises to profound scientific considerations that reveal the vast knowledge he possessed in sciences. It has been said that with this book, Zag Sujurmenza reformed the character of the science of astronomy and contributed to its advancement, without losing sight of the studies of Arab scholars, following in their footsteps and correcting their errors. Other works of Zag de Sujurmenza, if less extensive, are not without merit.
See also
*
Toledo School of Translators
The Toledo School of Translators ( es, Escuela de Traductores de Toledo) is the group of scholars who worked together in the city of Toledo during the 12th and 13th centuries, to translate many of the Judeo-Islamic philosophies and scientific w ...
*
Literature of Alfonso X
*
Book of knowledge of astrology
*
History of sundials
A sundial is a device that indicates time by using a light spot or shadow cast by the position of the Sun on a reference scale. As the Earth turns on its polar axis, the sun appears to cross the sky from east to west, rising at sun-rise from ben ...
*
Libros del saber de astronomía
The , ( osp, Libro del saber de astrología), "Books of wisdom of astronomy/astrology of King Alfonso X of Castile", is a series of books of the medieval period, composed during the reign of Alfonso X of Castile. They describe the celestial bodies ...
he Books of the Wisdom of Astronomy by King Alfonso X, the Learned
External links
Los Libros de los relojes de Alfonso X el Sabio ooks of the Clocks of Alfonso the Wise"Las ciencias exactas y físico-naturales", by Julio Samsó("The court of Spain in the 13th century", "scientific works of Alfonso X: translations and original works"...)
Los Astrolabios y los Nocturlabios: Los primeros utensilios portátiles para medir la posición y el tiempo.(images from Libros del saber de astronomía
ooks of wisdom of astronomy of King Alfonso X the Wiseof Alfonso X el Sabio 13th century and various 13th-century astrolabes.)
References
*Rodriguez de Castro, Spanish Library
The content of this article incorporates material of Volume 70 of the
Enciclopedia universal ilustrada europeo-americana (
Espasa) with copyright before 1932, which is in the public domain.
{{authority control
Converts to Roman Catholicism from Judaism
Spanish Jews
Spanish Roman Catholics
Spanish translators
13th-century translators
13th-century astronomers
Medieval Spanish astronomers
Medieval Jewish astronomers