Thursday after Trinity Sunday
Sixty days after Easter, on the Thursday that follows Trinity Sunday, is Corpus Christi, or the Solemnity of the Most Holy Body and Blood of Christ. It is a celebration of the Eucharist or the Holy Communion where wine and bread are drank and eaten, representing the blood and body of Christ.
It was—and, to some degree, still is—believed that the wine and bread taken during the Eucharist was more than symbolic, and literally transformed into the blood and flesh of Jesus Christ upon ingestion, despite any evidence to the contrary. Miracles, or stories of miracles from other places or times past, were common on Corpus Christi and would be shared amongst parishioners.
Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord’s table, and of the table of devils.1 Corinthians 10:21, KJV
Corpus Christi was noted with mystery plays, where mummers players would act out biblical scenes. This was particularly popular in York, where a cycle of forty-eight plays were performed in rotation, depicting scenes from creation to the Last Judgement. Each play was performed by a guild, or group of traders and professionals from the city. They were suppressed during the Tudor period, however in the early 20th Century they were restored, and have grown in popularity again since.
Corpus Christi is observed by Catholics, but not particularly by any other church denomination. The mystery plays in York are regularly performed, with variations taking place each year as the form is experimented with.