Born Angelo Giuseppe Roncalli in 1881, Pope John XXIII is remembered as one of the most popular popes of all time.
Over the course of his tenure as pope, John XXIII initiated several reforms, which included summoning the first ecumenical council in almost a century. His dream of a united Christianity lead some to resist and others to celebrate his progressiveness.
Half a century after his death, Pope John XXIII is to be canonized on April 27 alongside Pope John Paul II in the Catholic Church's first-ever dual canonization.
Here is a look back at Pope John XXIII's life: