An 2000-year-old marble monument featuring the pagan god Mithras has been found outside Rome by Italian police who believe it was to have been illegally sold abroad. The large marble bas-relief which dates from the 2nd century AD was recovered by authorities in a house north of the capital, according to a report in the Italian daily, Il Messaggero.

Police said the monument was to be sold to China or Japan and transported via the United Arab Emirates.

The relief, made of white Carrara marble and weighing 1,500 kilogrammes, comes from Vejo - a former Etruscan city that flourished in the 5th century BC - and shows the god Mithras slaying a bull.

Agents from the Italian tax police or Guardia di Finanza said the piece was recovered from an old house in the Roman countryside.

According to a statement by Italian tax police, the operation "allowed us to also discover an archaeological site previously unknown to authorities."

Police said the tomb robbers were four Italians who planned to ship the piece to the UAE and then sell it on the Chinese or Japanese black market.

The illegal trafficking of antique artefacts is highly lucrative in Italy. The tomb robbers or 'tombaroli' steal the items from ancient graves and sites and later sell them on the international black market.

The cult of Mithras originated in Persia over 4,000 years ago, but was only one of the eastern deities. Rulers of the Roman empire worshipped Mithras for over 300 years.

Mithras worshippers held strong beliefs in a celestial heaven and an infernal hell, they believed in resurrection as well as judgement day and also drank wine and ate bread to symbolise the body and blood of the god.

The birth of the god was celebrated annually on 25 December.