The history of the town is obscure for many centuries after its destruction by the Teutonic barbarians; and for more than a hundred years the place remained waste and deserted, with the ruined buildings gradually becoming overgrown by trees and shrubs. Then, at the beginning of the sixth century, Theodo I., Duke of the Bojovarii, the founder of the Kingdom afterwards known as Bavaria, took possession of Salzburg and joined it to his own possessions. One account tells us that it was this Duke Theodo of Bavaria who, having become a Christian, summoned St. Rupert, after the latter had been driven from Worms, to Ratisbon with a view to his introducing Christianity into the Duchy. Tradition states that St. Rupert came to Juvavum about the year 582, or at the beginning of the seventh century, with the determination to make the spot his headquarters for the spread of the Christian faith. Duke Theodo appears to have made him a present of the ruined and deserted town and the country round about to the extent of an area of two miles square. Other estates and property were given him, including among many others those of Itzling, Oping (Upper Innsbruck), and a third part of the famous Hall Salt Spring. The Bishop set to work, and on the ruins of the old Roman settlement he soon established a town, building a convent and a church under the steep rocks of the Mönchsberg, where now the large Benedictine Convent and St. Peter's Church stand, in the latter of which the bones of the saint are said to lie buried. The Convent of Nonnberg had many estates granted to it, and became rich. Bishop Rupert appears to have also begun to build new dwellings and to have cultivated the land; not neglecting in the meantime the object for which he had come, viz. the spread of Christianity. He built many churches, and was the means of forming a large number of Christian communities throughout the Duchy. He also extended the influence of the town of Salzburg over the surrounding district, and when he died in 623 he left behind him, where he had found ruins, a flourishing town with religious institutions of considerable importance. It was from this settlement that the most powerful and wealthiest ecclesiastical principality in Southern Germany was destined to spring, which, though possessed in turn by various nations, lasted as a spiritual Principality until 1802, when it was secularized and re-established as a temporal electorate.