A big Thank You to Pope John XXII for this great feast!
'Really?' you cry, 'surely everybody knows it was ordered to be observed by Urban IV in 1264, through the bull Transiturus'. Well, yes, up to a point, Lord Copper. But the strange thing is that this bull had no ... or very little ... actual effect. It even appears (a strange crowd, the medievals) that the observance was not even kept in the papal court itself!!!. It was not until John XXII sent to the entire Western hierarchy, in 1317, a collection of decretals called the Clementines that it began to be universally observed. And Transiturus had not mentioned such things as Exposition and Processions of the Sacrament. Although there may be a very few refences to such activities between 1264 and 1317, it was after that date that a great wave of enthusiasm for the cultus of the Blessed Sacrament swept the Church.
Corpus Christi as you know it and love it results from John XXII seizing the moment when the devotional mood of the faithful was exactly ready for it.
Through most of the first 1200 years of the Church's history, there was no 'devotion to the Blessed Sacrament' as we know it. The Sacrament was indeed known to be truly the Body if the Lord and was reserved so that it could be administered to the sick. But there was no sense that it also afforded a focus for adoration and for a direct relationship with our Lord verily present. That was a precious gift of which the faithful became aware in the thirteenth and fourteenth centuries. And it was the example of what John XXII did when he had the Host carried in glorious rite through the streets of the papal city, Avignon, that was emulated throughout the Catholic world and which provided the pattern for what you are doing this Corpus-Christi-tide.
Three cheers for the Avignon papacy and for the greatest of the Avignon popes, John XXII!