For if my companions had not relied upon me and my knowledge of cosmography, there would have been no pilot or captain on the voyage to know within five hundred leagues where we were. Indeed, we were wandering with uncertainty, with only the instruments to show us accurate altitudes of the heavenly bodies: those instruments being the quadrant and astrolabe, as everyone knows. After this, everyone held me in great honor. For I truly showed them that, without any knowledge of sea charts, I was still more expert in the science of navigation than all the pilots in the world: for they know nothing of any places beyond those where they have often sailed before.