PORTO VECCHIO, PRELATURA NULLIUS of. — A city and prelature nullius in the State of Amazonas in Brazil. It has an area of 270,000 sq km with a population of 300,000 inhabitants, of whom 30,000 are Catholic. It has 2 parishes served by 11 secular priests and 2 male religious communities and 4 female religious communities (Ann. Pont., 1952, p. 642).
The prelature was established by Pope Pius XI with the apostolic constitution *Inter nostri* of 1 May 1925 by separating it from the dioceses of Amazonas and São Luís de Cáceres, elevating the existing church in P. V. to the status of a prelature. The prelature is suffragan to Belém do Pará; its first apostolic administrator was the Salesian Msgr. P. Massa (1925-46). It comprises the region of the Madeira River beginning from Tres Casas below Humaitá, extending into the State of Mato Grosso as far as the borders of the city of Guajará-Mirim. It includes part of the territory of the State of Amazonas, part of that of Mato Grosso, and part of the territory of Guaporé.