Supremi Apostolatus Officio ("The Supreme Apostolic Office") is an encyclical of Pope Leo XIII, issued on September 1, 1883, encouraging the practice of the devotion of the Rosary.^[1]

"Not only do We earnestly exhort all Christians to give themselves to the recital of the pious devotion of the Rosary publicly, or privately in their own house and family, and that unceasingly, but we also desire that the whole of the month of October in this year should be consecrated to the Holy Queen of the Rosary."^[2]