Italy, officially the Italian Republic, is a unitary parliamentary republic in Europe. Italy covers an area of 301338km2 and has a largely temperate climate; due to its shape, it is often referred to in Italy as lo Stivale (the Boot). With 61 million inhabitants, it is the 4th most populous EU member state. Located in the heart of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia, San Marino and Vatican ancient times, Greek, Etruscan, Celtic and other cultures have flourished in the territory of present-day Italy. Rome eventually emerged as the dominant power on the peninsula, conquering most of the "known world" as the leading political and religious centre of Western civilisation. During the Dark Ages, the Italian Peninsula faced calamitous invasions by barbarian tribes, but beginning around the 11th century, numerous Italian city-states rose to great prosperity through shipping, commerce and banking (indeed, modern capitalism has its roots in medieval Italy). Especially during The Renaissance, Italian culture thrived, producing scholars, artists, and polymaths such as Leonardo da Vinci, Galileo, Michelangelo and Machiavelli. Italian explorers such as Polo, Columbus, Vespucci, and Verrazzano discovered new routes to the Far East and the New World, helping to usher in the European Age of Discovery. Nevertheless, Italy would remain fragmented into many warring states, subsequently falling prey to larger European powers such as France, Spain, and later Austria. Italy would thus enter a long period of decline that lasted until the mid 19th century.