These plays, associated esp. with the feast of Corpus Christi, were called 'mystery plays' because they were put on by the *mystery, i.e. members of a *guild. They may have developed from liturgical drama acted within the church, or from religious processions through the city streets. They typically dramatised the whole of salvation history from the Fall of Lucifer to the Last Judgement, though not every cycle was so inclusive; some towns played only a Passion series, though no texts survive. The most characteristic form of staging was on pageant wagons that were moved from point to point through a city, as at York or Chester. They lasted from the late 14c to the Reformation; Kendal's play was still being acted at the start of the 17c. -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.