Catholic News Agency - Pope Leo XIII was particularly devoted to Our Lady of the Rosary... In his 1883's “Supremi Apostolatus Officio,” he echoed the words of the oldest known Marian prayer... “It has always been the habit of Catholics in danger and in troublous times to fly for refuge to Mary.”.. “This devotion, so great and so confident, to the august Queen of Heaven,” Pope Leo continued, “has never shone forth with such brilliancy as when the militant Church of God has seemed to be endangered by the violence of heresy … or by an intolerable moral corruption, or by the attacks of powerful enemies.”