With decades of civil war finally behind them, many early seventeenth-century French Catholic leaders poured their energy into promoting religious change and renewal. At the same time, however, they remained deeply bound to the past as they strove to shape a collective Catholic identity. Richelieu's Instruction du chrestien, written in 1618 while he was bishop of Lu on, provides a valuable lens for exploring the dynamic between old and new in this period. Published in numerous editions, the book includes individual lessons in French on the beliefs and behaviour required of 'good' Catholics. For Richelieu, the context of his instructions was equally important as their content; they were designed to be read aloud by priests to their parishioners during the weekly parish Mass. Richelieu thereby melded papal and Gallican themes in ways that helped to define early modern French Catholicism, notably the importance of vernacular lay catechesis on the one hand, and its liturgical setting within the Latin Mass on the other.