The observance of a period of fasting before Easter is very ancient, though the length and character of the fast varied from place to place in the early days. Writing in the 2nd and 3rd centuries, Irenaeus of Lyons and Tertullian in North Africa both mention preparatory fasts in the days leading up to Easter. By the 4th and 5th centuries, we see the fasting period elongated: both Athanasius’s and Cyril’s Festal Letters assume a 40 day fast, for example. There are, however, still debates over what counts as this “fast of forty days”…