You are hereHomeBARSeptember/October 1978How It Came About: From Saturday to Sunday The connection between the two is clearly established by several Fathers, see Tertullian, On Fasting 14; Augustine, Epistle to Casulanus 36, 34; cf. Rordorf, Sunday, 143. Join the BAS Library! Already a library member? Log in here. Institution user? Log in with your IP address.