Columbus used the Spanish word “riesgo” and not only as a mercantile, but also as a general concept able to define the probability of a harm. This chapter is dedicated to analyze the elaborated notion of risk, “riesgo” in Spanish, as it was used by Columbus in his letters and accounts and by Juan Escalante who wrote a treatise of navigation to describe the “Carrera de las Indias” or Route to the Indies. In both cases the word “riesgo” was used in a wider sense and it not only applied to the insurance of goods, as it happened in Medieval Mediterranean, but also to the whole of ships and the life of the crews. The concept of risk was growing up semantically and being more and more precise.