Diocese of Marsico Nuovo

The diocese of Marsico Nuovo was a Roman Catholic ecclesiastical territory in Basilicata, southern Italy, which existed until 1818. In that year it was united into the diocese of Potenza, to form the diocese of Marsico Nuovo and Potenza.

Marsico Nuovo is a city of the province of Potenza in Southern Italy. Its origin is obscure, but, after the destruction, by the Saracens, of the ancient Grumentum, the town grew in importance, and became under the Normans the seat of a county. It became an episcopal see, when Bishop Grimaldo of Grumentum established his residence there, retaining, however, his former title. There were bishops of Grumentum as early as the sixth century: it is said that a Saint Laberius or Saverius first preached the Gospel there.

Other bishops were:

Erected: 4th Century
Latin Name: Marsicensis
Metropolitan: Archdiocese of Salerno

27 June 1818: United with the Diocese of Potenza to form the Diocese of Potenza e Marsico Nuovo

...
Wikipedia