The Feast of Corpus Christi
The Solemnity of Corpus Christi commemorates the Eucharist; traditionally it falls on the Thursday after Trinity Sunday, although in some regions it is transferred to the following Sunday.
The Feast of Corpus Christi is the name of this feast celebrating the Holy Eucharist. The Institution of the Eucharist is celebrated on Maundy Thursday. However, the emphasis on the passion themes present in the Maundy Thursday celebration created the need for another day to focus entirely on the Eucharist itself. The Thursday after Trinity Sunday was chosen for the date of the Corpus Christi feast because it is a Thursday (the same day Christ instituted the Eucharist) and it is the first free Thursday after the Easter season (since the Thursday after Pentecost was a part of the ancient octave of Pentecost).
The Feast of Corpus Christi is celebrated throughout the Catholic Church. Typically Corpus Christi services consist of singing traditional hymns, Lauda Sion and Pange Lingua. Outdoor processions of the Blessed Sacrament are common as a way to celebrate Corpus Christi.