Exploration in antiquity was largely the result of commercial or military endeavours, rather than any pure quest for knowledge or scholarship. Nevertheless, from the first efforts of Greeks to move beyond the Greek heartland into the Black Sea and western Mediterranean, which began as early as the end of the Bronze Age, Greeks and Romans steadily explored around and beyond their world. By the late Roman period, almost all of the Eastern Hemisphere was known, with the exception of interior southern Africa and the far northeastern portions of Asia, and it was suggested that there might be other continents across the ocean. Despite an emphasis on trade and commercial contacts, there was also an increase in scientific and other scholarly knowledge. The beginnings of Greek exploration are apparent in the Odyssey of Homer and may go back to the latter part of the Bronze Age. By the latter 7th century bce, Greeks were moving outside of the Mediterranean to the Phoenician (later Carthaginian) trading cities such as Gadeira on the Atlantic. With the rise of the Persians, they began to learn about what lay to their east, and Alexander the Great created awareness of a world stretching as far as India. At the same time, Pytheas of Massalia explored the northern Atlantic as far as Iceland. The discipline of geography was invented by Eratosthenes of Cyrene in the latter 3rd century bce, and in the following century the explorer Polybius reached the Equator. Roman military operations in the north of Europe and the British Isles and trade journeys into central Africa meant those regions were brought into the sphere of knowledge of the Mediterranean world. Realization that the inhabited world, however vast, was only a small part of the total surface of the Earth led to theorization about other lands across the ocean, but there is no solid evidence that anyone from the ancient Mediterranean reached them and was able to report on them. By the latter 1st century bce traders became aware of Southeast Asia and China, and there were occasional contacts during the Roman period, but by the 2nd century ce the era of ancient exploration was at an end, and there was little further expansion of geographical knowledge until the Islamic period.