Pliny the Elader, Natural History 34.139
Indeed there have been some instances in which it has been proved that iron might be solely used for innocent purposes. In the treaty which Porsena granted to the Roman people, after the expulsion of the kings, we find it expressly stipulated, that iron shall be only employed for the cultivation of the fields; and our oldest authors inform us, that in those days it was considered unsafe to write with an iron pen. There is an edict extant, published in the third consulship of Pompeius Magnus, during the tumults that ensued upon the death of Clodius, prohibiting any weapon from being retained in the City.
פורסנא הצליח לכבוש את רומא וכפה על הרומאים הסכם משפיל.