c. first half of the 11th century / West Asia & North Africa
Ibn al-Haytham connects light, vision and experiment
The Book of Optics combines geometry, visual inquiry and experiments, explaining sight through light entering the eye rather than rays emitted from it.
The story
Working in Cairo, Ibn al-Haytham examined light, reflection, refraction and visual errors, stressing careful tests and inference. Institutions differ on the work's precise date, so this is an approximate period. He did not single-handedly invent a timeless scientific method; his work transformed earlier questions and was itself transformed in transmission.
Connections and context
Latin optical writers and Kepler continued investigating vision. What travelled included problems, arguments and experiments, not simply a genius's conclusions.
Dates and precision
c. first half of the 11th century Approximate year
An estimated date from the surviving evidence, not a claim about one exact year.
Representative map location
Cairo
His scholarly activity in Fatimid Cairo, not an identified building where the Book of Optics was composed.
Representative coordinates · 30.05°, 31.26°
A marker identifies one representative place, such as a manuscript collection, laboratory or observing site. It does not mean the work happened only there, or assign a shared discovery to one country.
Bibliography
- The UNESCO Courier and scholarly institutions | Ibn al-Haytham's optics
- University of St Andrews, MacTutor | Ibn al-Haytham
- The Institute of Ismaili Studies | Ibn al-Haytham or Alhazen
References are listed as plain bibliography titles. They support particular facts or context; a reference does not certify every interpretation in a story.