"As Reinhard
Wolters has demonstrated, this
reverse type commemorates the passage of the
lex Valeria
Cornelia, and it was struck in 5 AD either in
Lugdunum, but with inhabitants of
Rome as the intended audience, or possibly even by a
mint in the capital city itself. That law provided that ten elective centuries should be designated to preliminarily select consuls and praetors. Those ten centuries were named after Gaius and Lucius Caesars, which explains the X in the coin
type and the selection of the Gaius and Lucius
reverse type even after the deaths of the two princes. For this interpretation, dating, and
mint location, see
Wolters, 'Gaius and Lucius Caesars as Designated Consuls and Princes of the
Youth: the
lex Valeria
Cornelia and
RIC I, 205 ff.',
Chiron 32, 2002, pp. 297 ff."
That seems a little far-fetched, but not having read the article, I have no idea how convincing Wolters' arguments are!
What do you mean by "slow" English, by the way?