Roman Empire in 1st century AD

Italy was invaded several times in the fifth century by Goths, Huns, and Vandals. In 476 the empire in the West collapsed, paving the way for a period of wars between Goths and Byzantines for control of what had been the western empire. The conquest of Italy by Arian Lombards along with the declining power of the eastern portion of the empire prepared the way for a series of strong popes. The popes, most notably Gregory the Great, asserted political authority in Rome and created what would become the "Patrimony of Saint Peter," a collection of estates belonging eventually to other "States of the Church." These states were under the sovereignty of the pope and thus independent of any other political control. The tiny and independent Vatican City of the present is a remnant of these states.