Visitors look at a painting by Italian artist Michelangelo Merisi known as Caravaggio in June 2012
Italian art experts have reportedly discovered around 100 drawings and a number of paintings by the Renaissance master Caravaggio in a find that could be worth over $860 million.
Maurizio Bernardelli Curuz and Adriana Conconi Fedrigolli found the works among a collection held at Milan's Sforza Castle by pupils of painter Simone Peterzano with whom Caravaggio studied from the age of 11.
The pieces were the work of a "strong, quick... hand" showing "the faces, bodies and scenes the young Caravaggio would use in later years," Bernardelli Curuz was quoted as saying by La Repubblica daily.
Photographs of the works, extracts of which were published in the Italian media Thursday, ranged from preparative anatomical sketches to religious scenes.
The newly unearthed works could be worth around 700 million euros ($867 million) according to the two experts who have been studying the paintings for two years, the ANSA news agency said.
"It was impossible that Caravaggio had left no trace of his activity between 1584 and 1588 at the workshop of a painter who was famous and sought after at the time," Bernardelli Curuz told La Repubblica.
The estimate of their worth is based on the average sale price at auction for drawings by Renaissance artists over the past few years.
Out of the 100 or so works found, details from 83 of them "can be traced several times in the later works, proving the young painter left Milan with styles, models, character heads" for his later works, Bernardelli Curuz added.
But while the art experts said the works found in the collection were clearly executed by Caravaggio, the city, which owns the drawings, has urged caution.
"The drawings have always been there, and have never yet been attributed to Caravaggio," said Elena Conenna, the council's culture spokeswoman, who said the city had not been informed beforehand and "will be carrying out checks."
"We'll be very happy to discover it's true. But it's strange. They weren't in a hidden place, they were accessible to all. While lots of experts come, these two have not been to see the works in the last two years," she said.
ANSA said the discovery came after a lengthy search through churches in the northern Italian city, as well as the collection of 1,378 drawings done by Peterzano and his students.
The works will be published on Friday in an e-book, along with "a protest written and signed by the young Caravaggio," the agency said.
Michelangelo Merisi (1571-1610), or Caravaggio, is known as one of history's most tormented painters. He was involved in frequent brawls and vicious beatings and fled Rome after being sentenced to death for killing a love rival.
Hailed as the master of the "chiaro-scuro" technique -- the contrast of shadow and light -- he died of fever in exile and was buried in a mass grave.