Meanwhile, Paul III gradually recovered the family lands around Castro which had been split after the death of Ranuccio the Elder. To this he added the territory of Ronciglione. Pier Luigi was invested with the titles of "Montalto" which gave the right to export grain without paying taxes; and Paul accepted feudal rights over Canine, Gradoli, Valentano, Latera and Marta. He exchanged the city of Frascati for the fortress at Castro, and at bought Bisenzio from the diocese of Montefiascone. As a final act, Paul created a formal duchy out of the lands and bestowed it upon his son and heirs. The duchy was, however, to come under the direct control of the Holy See.