Sicily is an autonomous region of Italy and the largest island in the Mediterranean Sea, with an area of 25,708 km² (9,926 sq. miles) and five million inhabitants. It has at times been a city-state and an independent kingdom. Sicily was originally colonized by Ancient Greeks, and then taken over by the Roman Republic and the subsequent Empire. Between the Middle Ages and the 19th century, Sicily was usually a colony or satellite state of the Holy Roman Empire, France, or Spain. After forming part of the Kingdom of the Two Sicilies, it became an autonomous part of the Kingdom of Italy in the 1860s, a status it retained after Italy became a republic in 1946.