BOSTON  — A Harvard University professor has unveiled a fourth century fragment of papyrus that she says is the only existing ancient text that quotes Jesus explicitly referring to having a wife.

Karen King, an expert in the history of Christianity, says the text contains a dialogue in which Jesus refers to “my wife,” whom he identified as Mary. King says the fragment of Coptic script is a copy of a gospel, probably written in Greek in the second century.

King unveiled the fragment of the “Gospel of Jesus’s Wife” in Rome on Tuesday. She says it doesn’t prove Jesus was married but speaks to issues of family and marriage that faced Christians.

King says on a Harvard website that the dialogue includes the disciples discussing whether Mary is worthy and Jesus saying “she can be my disciple.”