World Wide Words says this phrase was used in several Bible passages and by Shakespeare, but that it has been around “as long as the language.” The first recorded example was in the words of King Alfred at the end of the ninth century. Sight is considered to be precious, the pupil of the eye was called the apple, and to be called “the apple of my eye” was considered the highest form of endearment. The Latin original for pupil was pupilla, or “little doll.” “It was applied to the dark central portion of the eye within the iris because of the tiny image of oneself…that one can see when looking into another person’s eye.”