Complex sentence: Historians are certain de Caro lived and worked at that address, thanks to recently discovered documentation in the archives of the Banco di Napoli, whose archives hold the accounts books of what was known in the past as the "public banks of Naples".
Split into simpler sentences: Historians are certain de Caro lived and worked at that address, thanks to recently discovered documentation in the archives of the Banco di Napoli. This bank's archives hold the accounts books of what was known in the past as the "public banks of Naples".