0 ENCYCLICAL OF POPE PIUS XII ON THE UNITY OF HUMAN SOCIETY TO OUR VENERABLE BRETHREN: THE PATRIARCHS, PRIMATES, ARCHBISHOPS, BISHIOPS, AND OTHER ORDINARIES IN PEACE AND COMMUNION WITH THE APOSTOLIC SEE Venerable Brethren; Health and Apostolic Benediction. In the very year which marks the fortieth anniversary of the consecration of mankind to our Redeemer's Most Sacred Heart, the inscrutable counsel of the Lord, for no merit of Ours, has laid upon Us the exalted dignity and grave care of the Supreme Pontificate; for that consecration was proclaimed by Our immortal predecessor, Leo XIII, at the beginning of the Holy Year which closed the last century.
Source: Summi Pontificatus (Vatican.va)