Did the responses answer your question sufficiently?

The problem(s) are not really with the standard.
As you go back in time, UTC doesn't exist, time zones also become less well
defined, measurement of time becomes less accurate, the dates of conversion to
Gregorian vary around the world, political entities and borders change, and
often the author did not record his or her location and "time zone" when noting
an event.

The standard does say that when the standard is used to go earlier that there
should be an agreement among the parties using it.
Wikipedia could document its guidelines to ensure common semantics within
microformats.
Wikipedia can also define some additional metadata to ensure the assumptions
made when assigning a date-time with ISO8601 are kept with it so it won't be
misconstrued.

Note also the existence of a year zero, and guidelines on leap days for dates
before epoch.

tex

--- In ISO8601@yahoogroups.com, "pqrc96" <pqrc96@...> wrote:
>
> Some people who write in Wikipedia are interested in using
> microformats to provide a machine-readable version of important dates
> and times, in the hopes that future software will be better able to
> mine data from articles. Dates and times in microformat purport to
> conform to the ISO 8601 standard, but at least in the case of
> Wikipedia, the people interested in implementing this sort of thing
> don't have a clear understanding of time zones or the need to use
> the Gregorian calendar. Upon re-reading the standard to see if some
> of these items could be cleared up, I noticed that the standard has
> an oversignt, in that it allows for dates and times before the
> beginning of UTC but does not provide a way to specify a time zone
> for these dates, because doing so requires UTC. In a standard that
> is so careful to explain the meaning of every single character, this
> seems like an error. Of course, people will go ahead and extend it
> backward however they please, but strictly speaking, they are no
> longer using ISO 8601, they are using their own private extension.
>
> --- In ISO8601@yahoogroups.com, "johnmsteele" <johnmsteele@> wrote:
> > . . .
> > What are you trying to do exactly and what time records are you
> having
> > trouble relating to UTC?
>