Now a selection of the priceless works held by the Torlonia family, one of Rome's oldest dynasties, is finally to go on public view following an agreement this week between the Italian ministry of culture and the family foundation.
Under the deal, between 60 and 90 of the works in a collection which counts 620 pieces will be displayed in Rome in the second half of 2017.
An overseas tour is to follow before they are finally housed in a permanent centre in Rome.
Having amassed a fortune from banking in the 18th Century, the Torlonia family went on to become important collectors of antiquities and objects d'art, often accepting individual pieces as security against loans.
The bulk of the collection has spent decades in the basement of a family palace in the Trastevere neighbourhood of central Rome after Prince Alessandro Torlonia decided to convert the building into a 90-flat condominium.
Legend has it that curiosity over the treasures that lay below the block promoted renowned archaeologist Rannuccio Bianchi Bandinelli to disguise himself as a refuse collector in order to get in and check them out.
The Italian state has made repeated requests for the marble works to be handed over to public ownership, so far in vain.