The Arab scientist Ibn al-Haytham, known in Europe as Alhazen, wrote his seven-volume Kitab al-Manazir in Cairo between 1011 and 1021, partly while under house arrest by the caliph al-Hakim. He proved by experiment that we see because light enters the eye from objects, and not because the eye emits rays, as Euclid and Ptolemy had taught. He studied reflection, refraction, the camera obscura, the structure of the eye and the illusions of perception. Translated into Latin around 1200, his work influenced Roger Bacon, Kepler and Descartes, and he is often called the father of modern optics and of the experimental method.
Before and after
- from 1011 to 1934Construction of Saint Sophia Cathedral
- 1015Construction of Cathedral of Our Lady of Strasbourg
- 1020Death of Ferdowsi
- 1020Construction of Wawel Cathedral
- 1021Ibn al-Haytham completes the Book of Optics
- 1021Vikings are at L'Anse aux Meadows in Newfoundland
- 1024The Song dynasty issues the first government paper money
- c. 1020sAl-Biruni measures the size of the Earth
- 1025Avicenna completes the Canon of Medicine
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The era
This moment belongs to the Medieval world (500 CE to 1500 CE), kingdoms, faiths and trade routes. You can also browse everything in the 11th century.