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
Europe the EU. Malta was considered an island of Northwest Africa for centuries. "Europe" as used specifically in British English may also refer to Continental Europe exclusively. The first recorded usage of "Eurṓpē" as a geographic term is in the Homeric Hymn to Delian Apollo, in reference to the western shore of the Aegean Sea. As a name for a part of the known world, it is first used in the 6th century BC by Anaximander and Hecataeus. Anaximander placed the boundary between Asia and Europe along the Phasis River (the modern Rioni River) in the Caucasus, a convention still followed