While the surname is often associated with the aristocracy of Tarragona, the exhibition highlights that the family's origins lie in Vall Ferrera. Members of the clan ruled this area for hundreds of years before their eventual migration.

A key historical moment occurred in 1749, when Carles de Castellarnau i de Castellarnau moved to Tarragona. This relocation began an expansion that would lead them to become one of the most prominent families in Catalonia.

Visitors can explore ten centuries of history through this collection, which bridges the medieval past of Pallars Sobirà with the family's later social and political significance in the Tarragonès region.