The brief exhibition at the Capodimonte museum has been organized as a thank you to the southern city for the local police's role in tracking down the two small but hugely valuable and historically significant oil paintings.

The works had gone unheard of from the time they were stolen in a daring raid on the Van Gogh Museum until they turned up last year at the house of a notorious mafia boss.

The 1882 “Seascape at Scheveningen” and the 1884/5 “Congregation leaving the Reformed Church at Nuenen” were among the Dutch master's first oil paintings and, as such, are of enormous interest to art historians.

How exactly the paintings ended up in Italy remains a mystery.

They were found in September during a raid on a property belonging to fugitive mobster Raffaele Imperiale, at Castellammare di Stabia, southeast of Naples.

The area is a notorious hotspot for the nefarious activities of the Neapolitan mafia, the Camorra.

The paintings were stolen in December 2002 with the thieves using a rope to get in and out of the heavily fortified building after getting on to the roof by ladder.

Giorgio Toschi, a general with Italy's financial and customs police, said the theft had ranked on the FBI's top ten of art crimes.

“More than ever we are seeing art works being used by criminals either as safe haven investments or as a way of making payments or guaranteeing deals between organized criminal groups,” he said at the unveiling of the two paintings on Monday.