"Martyrdom of Saint Lawrence" was potentially attributable to Caravaggio, the Vatican announced in its official Osservatore Romano newspaper on Saturday, praising the painting, the property of the Jesuit Order, as "stylistically impeccable". A front page article compared the work, which shows the young saint crying out in pain as he is roasted over a grate, to other works by the master, including his "Conversion of St Paul" and "Martyrdom of St Matthew".
But the Vatican said that further study was needed before a reliable attribution could be made.
Not everyone was convinced of the painting's authenticity.
Antonio Pinelli, an art historian from Florence, said the detail of the painting published by the Osservatore Romano made him think of a follower of Caravaggio, rather than the great master himself.
Mr Pinelli said the texture of the saint's skin looked leathery and a blue loincloth had been poorly executed. "That blue rag is really a very poor thing," Mr Pinelli told La Repubblica newspaper.
Caravaggio, the high-living master of chiaroscuro, a technique in which the contrasts between light and dark are emphasised to dramatic effect, was born Michelangelo Merisi in Milan in 1571 and died in Porto Ercole in July, 1610.
Researchers announced recently that they were confident they had identified his mortal remains from previously anonymous bones buried in a church crypt in the Tuscan seaside town.
Rome marked the 400th anniversary of his death over the weekend by staging a free all-night exhibition of the Renaissance painter's works, which were exhibited in three churches, Santa Maria del Popolo, Sant'Agostino and San Luigi dei Francesi, and in the Borghese Gallery.