Deepertruth: Eucharistic Miracle, LIÈGE, BELGIUM, 1374, Establishment of Corpus

“Even though the Eucharist is solemnly celebrated every day of the year, on one day we pay special honor to the Body of Christ. We may, of course, invoke the Lord with our minds and our spirits at any time, but we do not in this way obtain the Real Presence of Christ. With the Eucharistic commemoration, however, Jesus Christ is actually present with us in his own substance. As the risen Christ told us prior to his Ascension: ‘And behold, I am with you always, until the end of the age.’ (Mt.28, 20) …He would remain and be with them even by His bodily presence.” Pope Urban IV: TRANSITURUS DE HOC MUNDO

Blessed Juliana of Cornillon, who lived in 13th century Belgium, had a vision in which she saw a full moon darkened in one spot. She heard a mysterious, heavenly voice state that the moon represented the Church at that time, and the dark spot showed that a great feast in honor of Corpus Christi was missing from the liturgical calendar. 

She reported this vision to the local ecclesiastical authority, the Archdeacon of Liège, Jacques Panteléon, who was later to become Pope Urban IV. In 1246, the Bishop of Liège, Roberto of Thourotte, established within his diocese a feast in honor of the Holy Sacrament, and it was celebrated for the first time on June 5, 1249. 

In 1264, Pope Urban IV (the former Archdeacon of Liège, to whom Blessed Juliana reported her vision) issued a papal bull extending the celebration to the universal Church. He also commissioned St. Thomas Aquinas to compose the Office for the Mass and Liturgy of the B Hours for the feast.