New Controversies on Columbus' "Cosmographic" Ideas (original) (raw)

On the basis of modern works of a Spanish paleographer, a North American geographer and, a historian-sailor, also North American, respectively, we have reexamined some controversial aspects of the "cosmographic" ideas ascribed to the Columbus brothers (Christopher and Bartholomew), regarding the preparation of their first transoceanic voyage. First, we present a discussion of two versions of the translation and explanation of a part or phrase of one of the marginal notes or postils, written supposedly by one of them or both in Latin in their IMAGO MUNDI (d'Ailly, Pierre. Tract of Geography of century XV) copy that seriously questions the credibility of the Columbus brothers' knowledge of the cartography of that time. Secondly, we have analized three hypotheses attempting to explain the methods they could have used, to measure the length of a terrestrial degree either on the equator or on a meridian. We will show that these hypotheses are unacceptable due to the manipulation of the information by its authors and, because there is not enough historical evidence to demonstrate that Christopher Columbus or his brother made such geodesical measurements.