Harvard divinity professor Karen King unveiled the 4th-Century Coptic script at a conference in Rome.

She said researchers had identified the words "Jesus said to them, 'my wife'", which might refer to Mary Magdalene.

Christian tradition holds that Jesus did not marry - but Ms King said in early years it was subject to debate.

The provocative find could spark debate over celibacy and the role of women within Christianity, she added.

But the announcement sparked scepticism from some theologians.

Jim West, a professor and Baptist pastor in Tennessee, said: "A statement on a papyrus fragment isn't proof of anything. It's nothing more than a statement 'in thin air', without substantial context."