Pope Francis has chosen 21 new cardinals in a move that once again shows his determination to reshape the group of churchmen who will elect his successor.

At the pope's death or resignation, cardinals enter into a secret conclave, where those under the age of 80 vote on the next pope. At least 67 countries now have cardinals who can vote in a conclave, according to Vatican statistics, compared to fewer than 50 countries when Francis was elected in 2013.

Pope Francis named 21 new cardinals Sunday, significantly increasing the size of the College of Cardinals and further cementing his mark on the group of prelates who will one day elect his successor.