This was the only authoritatively prescribed fast known to Tertullian (De jejunio, 2, 13, 14; De oratione, 18).
The latest extant works of Tertullian (all after 217) are his controversial writings against the laxity of the Catholics, full of the bitterest attacks, especially upon Calixtus, the bishop of Rome; these are De monogamic, De jejunio, De pudicitia, and De ecstasi Libri VII.
In the Liber Sad-der, indeed (Porta xxv.), we read, " Cavendum est tibi a jejunio; nam a mane ad vesperam nihil comedere non est bonum in religione nostra "; but according to the Pere de Chinon (Lyons, 1671) the Parsee religion enjoins, upon the priesthood at least, no fewer than five yearly fasts.
Bellarmine (De jejunio) distinguishes jejunium spirituale (abstinentia a vitiis), jejunium morale (parsimonia et temperantia cibi et potus), jejunium naturale (abstinentia ab omni prorsus cibo et potu, quacunque ratione sumpto), and jejunium ecclesiasticum.