The medieval parish church was central to most people's lives, and the Mass, the characteristic pre-Reformation service, exercised a defining influence upon the lives of clergy and laity alike. The laity were expected to attend Mass every Sunday and Holy Day; for many daily Mass was also a reality. The role of the Mass was enhanced by the dominent belief in Purgatory, since celebration of Masses reduced the length of time the soul remained there. All this was swept away by the sixteenth-century Reformation. This book, written by authors from different disciplines, explores the importance of late-medieval parish religion against the backcloth of medieval York. How many Parish churches were there? What was the form of the Mass and how was it celebrated? How were the church interiors arranged and how were they decorated? What contribution did music make? What was it like to be a cleric at the time? What changes did the Reformation bring? A substantial appendix provides a reconstruction of the pre-Reformation Mass as celebrated in York.