For “pastoral reasons,” the Catholic Church has moved the celebration of Corpus Christi to this Sunday. Historically, the feast of Corpus Christi has always fallen on the Thursday after Trinity Sunday, a way of celebrating the institution of the Eucharist outside of its more penitential setting on Holy Thursday. Thomas Aquinas was largely responsible for the texts of the Roman liturgy for this day as it was adopted in the 14th century, and it is to him that we owe the hymn whose incipit appears as the title of the site for the rest of the week.
I do not see a problem with this transfer, as it is increasingly becoming a trend in other countries, though I was reminded of why it fell on Thursday in the first place. But the office book I use has propers for a Thursday celebration. The other one I have has its own (different) propers which I will use for the Sunday, just so I can celebrate it with everyone else.
Meanwhile, while we are recovering from the high of Trinity Sunday (on which more will be said later), I would like to share a sermon preached by an editor of Ekklesia, one of my favorite Christian websites on the Trinity.