The rule of friendship means there should be mutual sympathy between them, each supplying what the other lacks and trying to benefit the other, always using friendly and sincere words.
Marcus Tullius CiceroThe first law for the historian is that he shall never dare utter an untruth. The second is that he shall suppress nothing that is true. Moreover, there shall be no suspicion of partiality in his writing, or of malice.
Marcus Tullius Cicero