 Throughout the Middle Ages the reflection on the concept of informatio is taken up by successive thinkers. Illustrative for the Aristotelian influence is the passage of Augustine in De Trinitate book XI. Here he analyzes vision as an analogy for the understanding of the Trinity. There are three aspects: the corporeal form in the outside world, the informatio by the sense of vision, and the resulting form in the mind. For this process of information Augustine uses the image of a signet ring making an impression in wax (De Trinitate, XI Cap 2 par 3). Capurro (2009) observes that this analysis can be interpreted as an early version of the technical concept of “sending a message” in modern information theory, but the idea is older and is a common topic in Greek thought (Plato Theaetetus 191c,d; Aristotle De Anime, Book II, Chp. 12, Book III, Chp. 4; Theophrastus De Sensibus 50).