Sentence:  Howard Williams' "The Ethics of Diet", was a 'biographical history of the literature of humane dietetics from the earliest period to the present day'. It tried to make out, that all philosophers and prophets from Pythagoras and Jesus down to those of the present age were <WSD>vegetarians</WSD>. 
Meaning of the word marked with <WSD> tags:  A person who does not eat animal flesh, or, in some cases, use any animal products. (from 1839)