The New World is one of the names used for the Western Hemisphere, specifically the Americas, certain Atlantic and Pacific oceanic islands to which the closest continental shelf is that of the Americas (such as Bermuda), and sometimes Oceania (Australasia). The term originated in the early 16th century, shortly after America was discovered by in the age of discovery, expanding the geographical horizon of the people of the Middle Ages, who had thought of the world as consisting of Africa, Asia, and Europe only: collectively now referred to as the Old World. The term was first coined by Florentine explorer Amerigo Vespucci. The Americas were also referred to as the "fourth part of the world".