[Just coming late to this discussion, so sorry if this has already be talked out.] 1) For BCE dates my gut feeling is that the spec should support _naming_ the years in normalized, numeric format rather than _calculating_ the years from supposed 0 or -1 positions. If it is generally agreed in the Western world that the name of a year is 31 BCE, then I would argue that the most appropriate normalized form of that is "-31" or BCE31 (as in John Kunze's TEMPER proposal). An approach based on calculation from another date is trying to solve a problem that I don't believe exists, in our domain at least. And maybe I'm missing something, but the following sentence from the table seems problematic on its face: "BC has no year zero. In the BC system the year before year 1 is '1 BC'. Thus '-0999' means '1000 BC'." Shouldn't that be "-1001" means "1000 BCE" (calculated from 1 BCE)? Or, if a scholar says something is from 1000 BCE, why wouldn't we assume that s/he knows that BCE starts with 1 BCE? BTW -- I would strongly encourage the use BCE and CE terminology in evolving standards documentation rather than BC / AD. 2) Using extensive "prescribed punctuation" to describe different types of dates (curly brackets, square brackets, single quotes, tildes, greater than/less than, double slash, and the infamous 'u' of old) is not a great way to build a modern standard. Giving unusual meanings to ordinary punctuation is not a substitute for appropriate, schema-driven content designation. I recognize that there is value in having a few simple metadata elements embedded in the date string and that ISO has already gone partway down that road. But asking us to write logic that parses things like: PT03HWI19990612T08:00:00/19990612T18:00:00 to explain "3 hours within the period between 8am and 6pm on 12 June 1999" seems over the top. (I hope and assume LC has solid use cases for each of these examples and isn't just speculating about possibilities!) At a certain point it would be best to fall back on schema-validatable approaches along the lines of: <dateCaptured><dateDelimiter point="start">19990612T08:00:00</dateDelimiter> <dateTimeInterval unit="hours">3</dateTimeInterval></dateCaptured> <dateDelimiter point="end">19990612T18:00:00</dateDelimiter> -- Anyway, just some quick thoughts. ---------------------------------- Stephen Paul Davis ~ Director, Libraries Digital Program 207A Butler, Columbia University Libraries, New York, NY email: [log in to unmask] ~ ph(212)854-8584 fax(212)854-0089