The last Pope to step down from office was Gregory XII back in 1415.
He resigned to end what was called the 'Great Western Schism,' when Christendom was divided by rival Popes.
"This was a way of restoring unity to a divided church," says James Bretzke.
Father Bretzke is a professor of moral theology at Boston College.
"He was considered to be a noble person in stepping down," Bretzke adds. "The Pope that had stepped down much earlier was cast by Dante into Inferno for stepping down. But Pope Gregory they considered that to be a noble move."