History of Vegetarianism-Vegetarian Diet
Pleas from vegetarians, remarks of individuals whose sentiments suggest they might be vegetarians—although history offers no proof—as well as remarks against cruelty of slaughter and eating of flesh document the history of vegetarianism.
Classical Antiquity; Early Church Fathers
Quotes Against Cruelty of Slaughter
[1st C. BCE-CE] Pythagoras Sotion taught me, why Pythagoras abstained from animal food, and why after him Sextius [1st c. BCE]: their reasons were different, but, both, very great. Sextius thought, that there was food enough for man in the world without shedding blood; and that the taking pleasure in butchering helpless animals, only inspired men with cruelty: he added hereunto, that luxury was not to be encouraged, and supposed of meats, and particularly such as are foreign to our constitutions are by no means a preservative of health, but the contrary.—Seneca, Epistles)
[1st c.] Ovid speaks of the Golden Age and Pythagorean Philosophy in his epic poem Metamorphoses.
Sencea, inspired by affection for Pythagoras Sotion, Pythagoras, and Sextius, "began to abstain form eathing flesh: I fancied my spirit more alert and free than it was before." He returned to eating meat at the request of his father having grown up in in the reign of Tiberius Ceasar who considered "abstinence from the flesh of certain animals," superstious and cause for bannishment from Rome.
First Essay on Abstinence from Animal Food Extant
[1st c.] Plutarch, On Eating Flesh—But for the sake of some little mouthful of flesh, we deprive a soul of the sun and light, and of that proportion of life and time it had been born into the world to enjoy. And then we fancy that the voices it utters and screams forth to us are nothing else but uncertain inarticulate sounds and noises, and not the several deprecations, entreaties, and pleadings of each of them.
[1st c.] Chaeremon the Stoic tells us in in Life of the Ancient Priests, that the ancient priests of Egypt "always abstained from flesh, " avoiding "even eggs and milk as flesh. The one, they, said was liquid flesh, the other was blood with the color changed? (Porphry, On Abstinence from Animal Food; Saint Jerome, Against Against Jovinianus)
[1st c.] Antiphanes, the Delian physician, said that this variety of viands was the one cause of disease—Clement of Alexandria, Instructor: On Eating
[1st - 2nd c.] Clement of Alexandia, The Instructor, On Eating
[2nd or 3rd c.] Sextus Empiricus informs us that "Pythagoras and Empedocles and the whole crowd of the Italian philosophers declare—that if we kill [animals] and eat their flesh we shall be doing wrong and committing a sacrilege, because we are destroying our kin. And it was for this reason that these philosophers recommended abstinence from animal food.
[2nd - 3rd. c.] Tertullian, On Fasting, In Opposition of the Psychics
[3rd c.] Plotinus refused such medicaments as contain any substance taken from wild beasts or reptiles: all the more, he remarked, since he could not approve of eating the flesh of animals reared for the table.—Porphyry, On Abstinence from Animal Food
[3rd c.] Porphyry, On Abstinence from Animal Food, Book 1-4;
But from all these, inanimate and slender food, and which is easily obtained, will liberate us, and will procure for us peace, by imparting salvation to our reasoning power. For, as Diogenes says, thieves and enemies are not found among those that feed on maize, but sycophants and tyrants are produced from those who feed on flesh.
Porphyry's forth book on Abstinence from Animal Food, although unfortunately mostly non-extant, would have likely provided the first comphrensive list of both Roman and Greek "individuals…in favour of abstinence from animal food".
[3rd c.] Mani and his followers, the Manichaens, in "abstaining from the slaughter of animals and from injuring plants" called "the destruction of a tree or of an animal murder," with the belief that "in the case of men, we have a community of rights…the same in the case of beasts and trees." (St. Agustine, Why the Manichaens Abstained from Animal Food)
[4th c.] St. Basil of Casearea, in his Homlies on Fasting, explains "In paradise, there was not yet any slaughtering of animals, not yet any eating of meat".
 Saint Jerome in his treatise Against Jovianius argues for abstinence from animal food as "pleasing to god" for "followers of wisdom, who devote themselves to the worship of God". As well for heatlh, advising men that "the same food that recovers health, can preserve it, for no one can imagine vegetable to be the cause of disease".
 Saint Jerome Care must be taken, therefore, that abstinence may bring back to Paradise those whom satiety once drove out. (Saint Jermome, Against Jovianius, To Eustochium , Letter 2-10, 26 )
[4th c.] St. Chrysostom speaks of a fearless "angel's table," without "streams of blood…nor cutting up of flesh".