Augustine, Confessions IV.2.3:
I remember once, that when I had a mind to put forth myself for the prize in a theatrical poem, I was demanded by I know not what wizard (haruspicem), what I would give him, to be assured to win the garland: but I detesting and abhorring such filthy rites, returned him answer; that though the garland were immortal and of gold, yet would I not suffer a fly to lose its life to gain me the better of it. For he was to kill certain living creatures in those his sacrifices, and by those honors to invite the devils (daemonia) to favor me. (Loeb trans.)