The biggest development in European medieval theater begins with a free-thinking scholar questioning how bread can become the literal body of Christ. When Berengar of Tours was himself a student, he studied under a former student of Gerbert of Aurillac, who became Pope Sylvester II (see my linked archived article). Now the dean of the cathedral school at Chartres, Berengar was one of the most influential thinkers of his time. His questioning drew attention to a theological question that had never been fully pinned down before: just how is the bread the body of Jesus? Berengar guessed that it “was” both things at the same time in some sense, but not literally.
The subsequent letters and hearings devoted to judging Berengar’s orthodoxy led to the Church forming an official doctrine that the bread mystically and miraculously becomes the literal body of Christ at the moment when the priest raises it. The term “transubstantiation” first came into use not long after, around 1125. In 1215, the Fourth Lateran Council determined that transubstantiation was the official doctrine of the Roman Catholic Church. In 1246, the Bishop of Liège began to have a regional feast day to celebrate the miracle of transubstantiation: the Feast of the Body of Christ, that is, Corpus Christi. In 1264, it became an official feast day of the entire Catholic Church. The idea was to form a procession through the town with an elevated Host — post-miracle — and allow everyone in the town to see it, for a blessing. They could also focus on education about the doctrine, to make sure everyone understood it. Even then, it wasn’t until 1317 that Popes really began to promote it.
During the 13th century, the church was also discouraging clergy from participating in plays outside the church. In 1210, the Pope had issued an edict forbidding them from going on a public secular stage. So over the course of the century between this edict and the promotion of Corpus Christi Day, the transition from church interior to church steps to public stage was complete.
The highlight of the Feast of Corpus Christi became the town’s Passion Play, a set of plays devoted to illustrating the story of Jesus’ death and resurrection, thus explaining the meaning of the Host. All over Europe, the tradition caught on. In Germany, by 1380, the play in Frankfort took plays over two days, it was so long. The plays grew more and more magnificent, so that by 1500, the Passion Play in Tyrol, Germany, it took seven days! It wasn’t enough to tell the story of Jesus’ life and death, so instead, the story began at the beginning of time, in Genesis.
I’m going to write in more detail, though, about the Corpus Christi plays in York, England. They’re interesting because they used stage wagons, and because they were a true civic project put on by the guilds. We have a lot of documentation, too. The guilds kept all sorts of records, so naturally historians have written all sorts of articles about aspects of the production.