This topic was brought up before, and though we may try to rationalize out another 'domini', there's one problem that remained back when it was talked about before, and still remains: that it's in Latin. That's indisputable, and Latin comes up several times in the series, whether Miguel's 'res nullius' or the badly translated 'angelus errare.' The point is, Latin exists. And if Latin exists, barring that we assume it's just being used for 'interest's' sake, Rome had to have existed. One way of rationalizing it, which I did long ago when I wrote a fanfic, was that Rome and all that did indeed exist, but that the Chronoverse rests along a seperate time-line in which the Mystics arose, hence altering things entirely. After all, apart from that, the next oldest thing we have is Zeal, in 10,000 BC... that does not technically conflict with history, or does not do so neccessarially, especially as Zeal is considered to only be a legend even in the Chronoverse.
Of course, CE, in using Cedric, probably makes more use of the Latin being merely for interest's sake, and therefore we can take AD and BC as the same. We can't in that case say they are supposed to technically mean anything, more than they figuratively stand for something.
