“Geography” by Claudius Ptolemy and European Instrumental Cartography in the 15th–16th Centuries

It is universally accepted that the early 15^th century Latin translation of the Greek manuscript of Claudius Ptolemy’s “Geography Manual” was the decisive event in the development of European instrumental cartography. A detailed analysis of the circumstances surrounding the translation of the “Manual” reveals a more complex picture. The first translation of the manuscript by the Florentine Jacopo d’Angelo attracted the humanists not for its mathematical part. They readily adopted the image of the world (imago mundi) proposed by Ptolemy and enthusiastically discussed the toponymics and descriptive geography in the treatise, and largely ignored its mathematical aspect – the geographic grid and the projection of a sphere onto a plane. It was only after Johann Regiomontanus’s criticism in the 1460s that the mathematical part of the treatise was completed and duly appreciated. The article shows that, in the course of almost a century-long assimilation of the treatise (which in humanist translation practice began to be commonly called “Geography”) the Renaissance scholars introduced a number of innovations into cartography that are lacking in Ptolemy’s treatise, and completely changed the methodology of instrumental measurements. Rather than talk about the direct inheritance of Ptolemy’s ideas by the Renaissance cartographic practice, it would, therefore, be more correct to talk about creative reworking of his cartographic recommendations, in which the development of trigonometry in the universities of the German speaking lands and the instrumental practice of urban architecture played a significant role.