Ibn Battuta, Abu Abdallah 365through Arab Eyes, trans. Jon Rothschild (New York:
Schochen Books, 1985); Amidu Sanni, The Arabic Theory
of Prosification and Versification: On Hall and Nazm in Ara-
bic Theoretical Discourse(Stuttgart: In Kommission bei
Steiner Verlag, 1998).
Ibn al-Haytham, Abu Ali al-Hasan ibn al-Hasan, al-
Basra(al-Hazen) (965–1040)physicist, astronomer
Ibn al-Haytham, or al-Hazen, was born about 965 at AL-
BASRAin southern IRAQ, where he was probably educated.
In his youth he gained sufficient fame for his knowledge
of physics that he was called to EGYPTby the FATIMID
ruler AL-HAKIMto attempt to regulate the flow of the
Nile. Failing in this effort, he was disgraced but estab-
lished himself as a copyist of mathematical manuscripts.
He continued to practice this scribal art in CAIROfor the
remainder of his life but at the same time pursued scien-
tific studies and published a number of original works
and two catalogs of his own work.
ASTRONOMYThe primary objective of al-Hazen was the explanation of
phenomena by both mathematical and physical hypothe-
ses. His interest in astronomy was motivated by the per-
ceived discrepancy between an Aristotelian model of the
celestial spheres and a Ptolemaic mathematical model. His
On the Structure of the Worlddescribed the Aristotelian
world of four elements and the Ptolemaic celestial
spheres. In it he inserted a discussion of the perception of
lunar and solar eclipses based on his assumption that the
Moon and Sun were solid physical bodies. In On the Light
of the Moon,he refuted an ancient concept that the Moon
reflected the Sun’s light as a mirror does. Rather, he
believed that the Moon was self-illuminating. He also
believed that the eye received two primary impressions in
vision, light and color. Therefore, he concluded that only
a physical effect of the Sun’s light rays on the Moon ren-
dered the Sun’s color and light visible. This idea opened
the possibility of reconciling the ideas of ARISTOTLEand of
the quantitatively inclined Ptolemy.
OPTICSIbn al-Haytham’s greatest scientific achievements were in
optics. In the discussion of the nature of vision at the
beginning of his Thesaurus Opticus,he argued that light
physically affected the eye. From this he argued that the
assumption by mathematical opticians of emission of
visual rays from the eye, though useful for geometric anal-
ysis, was wrong. Light rays, rather, proceeded from the vis-
ible object to the eye and were always accompanied by
color. These mixed rays of light and color moved in all
directions from a visible object. They were perceived when
the object was in the visual field of the eye, each point on
the surface of the visible object emitting a ray perpendicu-
lar to the lens of the eye. The eye physically received only
the rays of light and color, and the mind interpreted the
patterns produced as forms at various distances. His work
on the theory of vision was translated into Latin in the late
12th or early 13th century and was the basis of all discus-
sions of optics in the West until the 17th century.
Ibn al-Haytham has been called a founder of modern
physics and was certainly one of the greatest Muslim stu-
dents of physical theory. He died in 1040.
Further reading:A. I. Sabra, “Ibn al-Haytham,” in
Dictionary of Scientific Biography 6.189–210; J. Vernet,
“Ibn al-Haytham,” Encyclopedia of Islam3.788–789.Ibn Battuta, Abu Abdallah(Shams al-Din Abu Abd
Allah, Muhammad ibn Abdullah ibn Battuta)(1304–
1369)Muslim traveler
Abu Abdullah ibn Battuta was a Berber, born in the city
of Tangier, Morocco, on February 25, 1304, into a family
of Muslim legal scholars. A devout Muslim himself, he
left Tangier at the age of 22 after finishing his education.
On June 14, 1325, he set out to make the HAJJ, the pil-
grimage to MECCA and MEDINA, planning to return
decades later in 1349.FIRST STAGE ACROSS
NORTH AFRICA TO DAMASCUS
Ibn Battuta took 10 months to cross North Africa, passing
through modern Algeria, Tunisia, and Libya, before arriv-
ing in ALEXANDRIA, the main port of Egypt. There he saw
the Lighthouse at Alexandria, one of the Seven Wonders
of the Ancient World. From CAIRO, Ibn Battuta traveled
up the Nile River to Aswan and then overland to the port
of Aidhab on the Red Sea. Forced to return to Cairo
because of local disturbances that disrupted travel, he set
out across the Sinai Peninsula to JERUSALEM. After seeing
the important sights of PALESTINE, Ibn Battuta traveled on
to DAMASCUS, where he arrived on August 9, 1326. There
he met some of the famous Islamic scholars in the
ancient city and even married.THE FIRST PILGRIMAGES
Ibn Battuta joined a pilgrim caravan in September of
1326 and journeyed south by the Derb-el-Haj, the main
pilgrim road to Medina and Mecca, for 55 days. After
reaching only Medina in mid-November, he headed off to
IRAQand stopped in al-Najaf in southern Iraq, a holy city
to the SHIITEsect of Islam. From there, he went south to
the port of al-Basra, making a side trip to Persia or Iran.
Back in Iraq he went on to BAGHDAD, still in ruins after
its sacking decades before by the Mongols in 1258. He
joined a caravan headed south for Mecca.EAST AFRICA, ANATOLIA,
AND THE MONGOLS
Ibn Battuta stayed in Mecca from September 1327 to the
fall of 1330, studying Islamic law. Using his knowledge to