Rome's history spans 28 centuries. While Roman mythology dates the founding of Rome at around 753 BC, the site has been inhabited for much longer, making it a major human settlement for almost three millennia and one of the oldest continuously occupied cities in Europe. The city's early population originated from a mix of Latins, Etruscans, and Sabines. Eventually, the city successively became the capital of the Roman Kingdom, the Roman Republic and the Roman Empire, and is regarded by many as the first-ever Imperial city and metropolis. It was first called ''The Eternal City'' (; ) by the Roman poet Tibullus in the 1st century BC, and the expression was also taken up by Ovid, Virgil, and Livy. Rome is also called "Caput Mundi" (Capital of the World). After the fall of the Empire in the west, which marked the beginning of the Middle Ages, Rome slowly fell under the political control of the Papacy, and in the 8th century, it became the capital of the Papal States, which lasted until 1870. Beginning with the Renaissance, almost all popes since Nicholas V (1447–1455) pursued a coherent architectural and urban programme over four hundred years, aimed at making the city the artistic and cultural centre of the world. In this way, Rome became first one of the major centres of the Renaissance, and then the birthplace of both the Baroque style and Neoclassicism. Famous artists, painters, sculptors, and architects made Rome the centre of their activity, creating masterpieces throughout the city. In 1871, Rome became the capital of the Kingdom of Italy, which, in 1946, became the Italian Republic.