Arabic optics is derived from Hellenistic optics and, one could even say, only from it. Arabic optics has borrowed from Hellenistic optics its questions, its concepts, its results, and even the different traditions into which it divided in the Alexandrian era. One could say that the first Arab scholars who worked on optics joined the school of Hellenistic authors-Euclid, Hero, Ptolemy, Theon, and plenty of others-and them only. Optics distinguishes itself for this reason from other sectors of Arabic mathematical sciences, astronomy for example, in the sense that it received no other legacies, non-Hellenistic, so minute was it, that pushed with some weight on its development.
This very narrow dependence, however, did not hold up the relatively precocious emergence of innovative research. Very quickly after the massive transmission of Greek writings, the history of the discipline became that of the rectification of these writings, the accumulation of new results and the renewing of the principal chapters. Two centuries sufficed to prepare for what was finally a true revolution, which marked for ever the history of optics, indeed, more generally, that of physics. It is this dialectical movement between a solid continuity and a profound rupture that it is our duty to describe, in order to grasp the progress of Arabic optics between the ninth and the sixteenth centuries.
Let us place ourselves in the ninth century, in the mid-ninth century, more exactly. The Arabic translations of Greek texts on optics appear side by side with the first researches written directly in Arabic in this discipline. This simultaneity-which has not been sufficiently emphasized-of translation and research is not the privilege of optics; it can be seen through all the mathematical disciplines, if not for the totality of ancient heritage. The simultaneity is for us of major importance if we want to understand the nature of the movement of the translation and elaboration of optics. Never passive, the translation seemed on the contrary linked to the most advanced