"Mystery Plays" are dramatized scripture. They were used to teach salvation history to the illiterate masses who did not understand Latin, the language of the Church, and therefore could not read it for themselves. (Recall that even the literate in a pre-print, manuscript culture did not have the easy access to books which we do today. Manuscripts were expensive and relatively scarce. Most lay people, even those who knew Latin, did not have copies of scripture to read and study on their own.) Unlike the theater of later periods, medieval Mystery Plays were NOT primarily presented as entertainment-- they were pedagogical tools not unlike sermons. But the effectiveness of a sermon depends in large part on the ability of the preacher to engage the interest of his audience. Dramatizations have the advantage of being lively and engaging. Since Mystery Plays were performed in the streets by ordinary citizens (the Guilds), not professional actors or priests, they doubly engaged their audience: those who performed in them must have felt a part of the stories they were enacting, while the audience witnessed biblical narratives "coming to life" with a very familiar and human face. While Mystery Plays were undoubtedly fun to watch, the underlying purpose was serious: to engage the interest and understanding of the audience in order to help them be better Christians. Medieval theater is thus very different in its purpose from the theater of the Renaissance (and beyond), when plays were performed by troupes of professional actors whose primary goal was to support themselves by ENTERTAINING ticket-buyers.

Mystery plays came in CYCLES: a series of plays which together were meant to present ALL OF SACRED HISTORY, from the Creation of the world through the End of Time (the Last Judgment), with particular emphasis on human history: the Fall of mankind (Adam and Eve eat the apple in the Garden of Eden) and the consequences of that Fall (other Old Testament stories illustrating man's sin or prefiguring redemption; ex: Noah's Ark); the way Original Sin was redeemed through the Nativity, Incarnation and Passion of Christ (source: New Testament and apocrypha for, e.g., the Harrowing of Hell); finally, the end of the world, when humanity rises from the dead to face the Last Judgment. Our reading is a dramatization of the Nativity of Christ-- a New Testament event that dovetails nicely with the special reverence for Mary which we have noted in other works of the Middle English period (in particular, the Marian lyrics, but also e.g. Sir Gawain and the Green Knight).