BTW, what *are* the other systems likely to be encountered? Muslim and Jewish are all I can think of, but maybe the Baalists have some preference that hasn't come to my agnostic
attention.
Don't forget the eastern schemes! The Chinese calendar is far more widely used than the western alternatives to the BC/AD scheme, if only because it had less cultural contact with the main force for standardizing dates in Europe -- the Roman Catholic Church (which drove standards because they wanted everybody celebrating the same feasts on the same day).
Mark Christensen