Feast of the Body of Christ
This feast is celebrated in the Latin Church on the Thursday after Trinity Sunday to solemnly commemorate the institution of the Holy Eucharist. Maundy Thursday commemorates this great event; mention is made as Natalis Calicis (Birth of the Chalice) in the Calendar of Polemius (448) for 24 March, 25 March being in some places considered as the day of the death of Christ. This day, however, was in Holy Week, during which the faithful are expected to meditate on the Lord's Passion. Also, with so many other functions on this day, the principal event was almost lost. This is mentioned as the chief reason for the introduction of the new feast in the Bull Transiturus.
The instrument for the creation of this feast was Saint Juliana of Mont Cornillon, in Belgium. Juliana, from her early youth, had a great veneration for the Blessed Sacrament, and always longed for a special feast in its honour. This desire is said to have been increased by a vision of the Church under the appearance of the full moon having one dark spot, which signified the absence of such a solemnity. She made known her ideas to Robert de Thorete, then bishop of Liège, to the learned Dominican Hugh, later cardinal legate in the Netherlands, and to Jacques Pantaléon, at that time Archdeacon of Liège, afterwards bishop of Verdun, Patriarch of Jerusalem, and finally Pope Urban IV. Bishop Robert was favourably impressed, and, since bishops had the right of ordering feasts for their dioceses, he called a synod in 1246 and ordered the celebration to be held in the following year. A monk named John wrote the Office for the occasion, and the feast was celebrated for the first time by the canons of Saint Martin at Liège.
The recluse Eve, with whom Juliana had spent some time, and who was also a fervent adorer of the Holy Eucharist, urged Henry of Guelders, Bishop of Liège, to request the pope to extend the celebration to the entire world. Urban IV, an admirer of the feast, published the Bull Transiturus on 8 September 1264, in which he ordered the annual celebration of Corpus Christi on the Thursday next after Trinity Sunday; he also granted many indulgences to the faithful for the attendance at Mass and at the Office. This Office, composed at the request of the pope by Saint Thomas Aquinas, is one of the most beautiful in the Roman Breviary.
The death of Pope Urban IV shortly after the publication of the decree somewhat impeded the spread of the festival. Clement V again took the matter in hand, and at the General Council of Vienne in 1311, ordered the adoption of the feast. He published a new decree which embodied that of Urban IV. John XXII, successor of Clement V, urged its observance.
The feast had been accepted in 1306 at Cologne; Worms adopted it in 1315; Strasburg in 1316. In England it was introduced from Belgium between 1320 and 1325. In the United States and some other countries the solemnity is held on the Sunday after Trinity. In the Greek Church the feast of Corpus Christi is known in the calendars of the Syrians, Armenians, Copts, Melchites, and the Ruthenians of Galicia, Calabria, and Sicily.abridged from an article in the Catholic Encyclopedia