Some excellent historical information can be found at The Way of the Father about this feast and about the reality for the Church from the beginning.SOLEMNITY OF THE MOST HOLY BODY AND BLOOD OF CHRIST
This Solemnity goes back to the thirteenth century. It was first established in the diocese of Liége, and Pope Urban IV instituted it in 1264 for the whole Church. The meaning of this feast is the consideration of and devotion to the real presence of Christ in the Eucharist. The center of the feast was to be, as Pope Urban IV described it, a popular devotion reflected in hymns and joy. In the same year Saint Thomas Aquinas, at the Pope's request, composed for this day two Offices which have nourished the piety of many Christians throughout the centuries. In many different places the procession with the Monstrance through specially bedecked streets gives testimony of the Christian people's faith and love for Christ, who once again passes through our cities and towns. The procession began in the same way as the feast itself.
In places where the Solemnity of the Most Holy Body and Blood is not observed as a holy day of obligation, it is kept on the Sunday after the Most Holy Trinity as its proper day.
For many years God fed manna to the people of Israel as they wandered in the wilderness. This was an image and symbol of the pilgrim church and of each individual who journeys towards his or her definitive homeland -- Heaven. That food given in the desert of Sinai is a figure of the true food, the Holy Eucharist. This is the sacrament of the human pilgrimage ... Precisely because of this, the annual feast of the Eucharist that the Church celebrates today contains within its liturgy so many references to the pilgrimage of the people of the Covenant in their wanderings through the wilderness (John Paul II)....
Today is a day of thanksgiving and of joy because God has wanted to remain with us in order to feed us and to strengthen us, so that we many never feel alone. The Holy Eucharist is the viaticum, the food for the long journey of our days on Earth towards the goal of true Life. Jesus accompanies us and strengthens us here in this world, where our life is like a shadow compared to the reality that awaits us. Earthly food is a pale image of the food we receive in Holy Communion. The Holy Eucharist opens up our hearts to a completely new reality.
In Conversation With God Vol 6
Daily Meditations, Special Feasts: January - June