Sea in culture of barbarian invaders and knowledge of geography took a backward step. In the seventh century, Isidore of Seville produced a "wheel map" in which Asia, Africa and Europe were arranged like segments in an orange, separated by the "Mare Mediterranean", "Nilus" and "Tanais" and surrounded by "Oceanus". It was not until the fifteenth century that Ptolemy's maps were used again and Henry the Navigator of Portugal initiated ocean exploration and maritime research. Encouraged by him, Portuguese navigators explored, mapped and charted the west coast of Africa and the Eastern Atlantic and this knowledge prepared the way for the great voyages
Geography of Asia to Scythia. The relatively recent study of plate tectonics has discovered that Asia has several regions that would be considered distinct landmasses if strictly geologic and tectonic criteria were used (for example, South Asia and East Asia). Definition of "continental plates" is the realm of geologists. Strictly in terms of geological landmasses or tectonic plates, Europe is a western peninsula of Eurasia and of the Africa-Eurasia landmass. In the latter, Europe and Asia are parts of the Eurasian plate, which excludes the Arabian and Indian tectonic plates. In human geography, there are several schools of thought. The more common school