From left, Cardinal Kurt Koch, President of the Pontifical Council for Promoting Christian Unity, President of the Lutheran World Federation Bishop Munib Younan, Pope Francis, and General Secretary of the Lutheran World Federation Rev. Martin Junge, during an ecumenical prayer at Lund's Lutheran Cathedral, in Sweden, Monday, Oct. 31, 2016. Francis traveled to secular Sweden on Monday to mark the 500th anniversary of the Protestant Reformation, a remarkably bold gesture given his very own Jesuit religious order was founded to defend the faith against Martin Luther's "heretical" reforms five centuries ago. (AP Photo/Andrew Medichini, pool)