Complex sentence: The Order was founded in Belfast in 1915 by Canon James K. O'Neill, who was greatly influenced by the social teaching of the Catholic Church and particularly Pope Leo XIII's encyclical "Rerum Novarum".
Split into simpler sentences: The Order was founded in Belfast in 1915 by James K Cannon O'Neill. He was greatly influenced by the social teaching of the Church and particularly the encyclical "Rerum Novarum".