Sometime in the first few years of the fifth century a deacon at Carthage began to feel discouraged about his work and wrote for advice to St Augustine. His letter prompted the short treatise known as De Gatechizandis Rudibus, a book on the matter and method to be used the preliminary instruction of would-be Catholics, which was to become one of the best known and influential of Augustine's works. Io considering the personal worries of the deacon Deogratias, he laid down principles whose force has in no way lessened with time. The treatise has all the psychological wisdom and the epigrammatic vigour which so often make Augustine's writings sound almost contemporary in modern ears. It springs from experience, as its illustrations show, and the repeated assurance that the problems of Deogratias were common to all engaged in routine instruction.