Italian researchers said today they were almost certain that remains found in a church in Tuscany were those of Renaissance master Caravaggio, who has gone 400 years without a proper burial.

"The bones of one of the individuals found in the crypt of the cemetery church in Porto Ercole belong to Michelangelo Merisi da Caravaggio, with an 85 percent probability," they said in a statement.

The researchers from four Italian universities based their conclusion on DNA, carbon dating and other analysis over an investigation lasting a year which also suggested the artist suffered from syphilis, lead poisoning and sunstroke, they said.

Caravaggio's unmarked grave was thought to have been among around 200 at a small church cemetery in Porto Ercole. The remains were exhumed in 1956, then placed together in an ossuary in the church's crypt.

The researchers combed through all the remains before determining that a set belonging to a man who would have been aged 38 to 40 and died in around 1610 were those of Caravaggio.

The artist was said to have died of malaria in the marshy southern Tuscan region of Maremma in 1610 when not yet 40.

But the researchers also said suspicions that he suffered from syphilis were "likely" correct, and that the analysis revealed an abnormally high content of lead in the bones, confirming accounts blaming lead poisoining for Caravaggio's notorious temper.

"Regarding the cause of death ... we consider assumptions of general infection and especially of sunstroke to be fully credible," the statement added.

The artist, who revolutionised painting with his "chiaro-scuro" technique -- the contrast of shadow and light -- is celebrated for works including "Bacchus", "The Supper at Emmaus" and "Sacrifice of Isaac".

Caravaggio's subjects ranged from gambling to biblical episodes, but also illustrated his own turbulent life.

Michelangelo Merisi da Caravaggio arrived in Rome poor, then won fame and recognition before suddenly having to leave the city in 1606 after he was involved in a tavern brawl that left a man dead.

The work of the Caravaggio Committee, which included microbiologists, art historians and anthropologists, was coordinated by forensic anthropologist Giorgio Grupponi of the University of Bologna.

Nearly 600,000 people visited an extensive exhibition honouring the quadricentenary of Caravaggio's death that closed in Rome at the weekend.