The sixteenth century witnessed a shift from a geography of limit to one of communication. The old idea of an oikoumene separate from the rest of the globe was destroyed. The margins of the oikoumene had shifted over the years, but the concept had remained for more than two millennia. Only a comparative few had ever discussed the world beyond, and even fewer had left any widely read, written legacy of voyages beyond the boundaries. These regions had remained unreachable and unknowable. Roger Bacon, John Mandeville, Marco Polo and other late medieval scholars and travellers had all spoken of an inhabitable torrid zone, and of the possibility of travelling to lands across the equator, yet the fear of its all-consuming heat was such that few dared attempt to break the southern bounds of the inhabitable world described by most of the classical geographical writers. Eventually, however, the pragmatic desire to find new trade routes to the East, coupled with an increasing number of scholarly works describing an inhabitable equatorial region, convinced enough men in command that the tropical zone might be entered and the equator crossed. The Portuguese entered the torrid zone, and the myth of a climatic confine to human inhabitation was demonstrably proved to have no foundation. At more or less the same time, the other great boundary of the ancient world – the all-enclosing Ocean – was transformed, when Columbus, building on the work of Peter d’Ailly and his own readings of Ptolemy, rather than thinking of the Atlantic as a limit to exploration, saw it as a pathway to Asia, and set sail for India. His alteration of Ocean from a boundary to a means of communication initially harmed traditional perceptions of geography more than the discovery of the Americas. Thereafter geographers and explorers alike tended to accept the existence of Ocean, but it rapidly became altered from a barrier to a series of transportation routes. The humanist geographers transformed the concept of Ocean, retaining the idea of its circumambient nature, but not the idea of limit. In doing so, they paved the way for a completely modern geography, because by transforming the way Ocean was perceived into seeing it as the key means for making the whole world interconnected, it laid the foundations of European overseas empires and global trade networks. Without a transportation route, there could be no globalisation.