être marqué à l'A

This expression is supposed to have originated in the custom of stamping French coin with different letters of the alphabet. The mark of the Paris Mint was an “A,” and its coins were supposed to be of a better quality than those stamped at provincial towns. But as this custom only began in 1418 by command of the Dauphin, son of Charles VI., and as the saying was known long previous, it is more probable that its origin is to be sought in the pre-eminence that A has always held in all Aryan languages, and that the French have borrowed it from the Romans. Compare Martial , ii. 57, and our A i, at Lloyd’s.