Struck under Roman Emperor Nerva, the following As weighs 8.75 g. and is listed as Cohen 17 or RIC II- 53. The reverse has Clasped Hands with legend of Concordia Exercitvvm. But in my coin, the engraver had clearly omitted the letter E and wrote EXRCIT instead of EXERCIT. I wonder how grave this error could influence the rarity of a coin? Did they strike many of it, after the initial error of the engraver. Or they just stopped after they found out the missing letter E.