In the fifteenth century, Portuguese ships edged southwards along the African coast, crossing the equator and circumnavigating the Cape of Good Hope, eventually arriving in India. In 1492, notoriously, Columbus and his crew sailed across the Atlantic Ocean hoping to find an easier, westwards route to the Orient, instead finding outposts of a New World. With these two initiatives, the Iberians irrevocably destroyed the framework of the world within which medieval and classical western European geographical theories had evolved. A geography of boundaries and limits began to be transformed into one of connectivity.

Although there were always writers who had questioned the widely believed classical theories about the edges of the earth, the Spanish and Portuguese voyages of exploration round Africa and the Americas in the last quarter of the fifteenth century were the chief catalyst for the creation of a new widespread approach to world geography. In the ensuing century a tussle took place to create a new understanding of the world that took account of a vast wealth of information about previously unimagined peoples and places, while not entirely countering the received wisdom of the ancients. By the end of the sixteenth century a new geographical framework became widely accepted throughout western Europe. It was one which remained firmly founded on classical theories, but which also argued that the entire world was made by God for human inhabitation and that Ocean was designed to connect all parts of the globe. The oikoumene or inhabitable world now embraced the sphere.

This chapter will offer a brief examination of the way in which the coinciding events of the European explorations, the Renaissance, and the sixteenth-century reformations were fundamental in creating new, overarching theories about the shape and nature of the world. Starting with definitions of descriptive and mathematical geography, the chapter explores why descriptive geography, which has a human focus, was so important in the reconceptualisation of space in the sixteenth century. It examines the theoretical distinctions between geography and cosmography in the Greek writers, and demonstrates why the concept of the bounded oikoumene was a fundamental aspect of the original Greek idea of geography. The chapter then offers a brief discussion of the limits of the oikoumene, arguing that there was a time-lag between discovering that these limits extended further than previously believed, and the acceptance of these discoveries and their geographical implications into western European society.