The history of Rome begins with the famous myth of its founding in 753 BC by the twin boys, Romulus and Remus, who were saved and raised by a wolf. There is no doubt that Rome has since fulfilled its destiny of becoming a great world city and the center of one of history's greatest empires. The first period of Rome's known history includes the rule of six kings. During this period, Rome began its journey to become a military and economic power with the establishment of its constitution. The seeds of the Roman Empire were sown in 510 BC, when the Romans established a new type of government under the rule of the upper classes. By 338 BC Rome was constantly expanding, and by 44 BC Julius Caesar was crowned as the first Roman Emperor. During the period between 31 BC and 476 AD, Rome experienced the greatest prosperity, while from 476 AD onwards, the Papal States were founded and the influence of the city of Rome declined, with the Roman state collapsing by the middle of the 14th century. The 16th century is characterized by the Renaissance, a time when some of Rome's most important works of art were created by artists such as Michelangelo, Donato Bramante and Raphael. Coming quickly into the near past of the city's most modern history, 1946 was the year the Italian Republic was finally founded, after many battles and wars, with Rome being proclaimed the capital.