Book of Optics
Ptolemy, in Alexandria, Egypt, had found a relationship regarding refraction angles, but it was inaccurate for angles that were not small. Ptolemy was confident he had found an accurate empirical law, partially as a result of slightly altering his data to fit theory (see: confirmation bias). Alhazen, in his "Book of Optics" (1021), came closer to discovering the law of refraction, though he did not take this step.