The diocese, now covering an area of 12,380 sq. km., has 161,371 inhabitants, of whom 160,000 are Catholics, distributed in 14 parishes served by 23 diocesan priests and 25 regular clergy; one seminary, 8 male and 14 female religious communities (Anuario Pontificio, 1951, p. 248).
It was established by Pius XI with the apostolic constitution *Notabiliter aucto* of 18 Oct. 1925, by separating it from the diocese of the Most Holy Conception of the civil province of Linares; the parish church dedicated to St Ambrose was raised to the dignity of a cathedral. It is a suffragan of Santiago de Chile.
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Bibl.:** AAS, 18 (1925), pp. 205-207.