before I contribute my thoughts to this thread, I'd like to introduce
myself, because this is my first posting to this list.
My name is Clemens Radl and I work for the Monumenta Germaniae Historica
(Munich, Germany). Currently we are digitizing all our editions of
medieval sources. See <http://www.dmgh.de> for more details, an English
language introduction can be found at
(this is a link to the wiki of DigitalMedievalist). For this project we
will, of course, tag lots of medieval dates and we'd like to do it the
But, as far as I understand the standards and this discussion, using the
date@value attribute correctly according to the TEI P5 would force us to
convert all dates to the proleptic Gregorian calendar, while in P4 it
was possible to use a normalized version of the Julian date fot this
While I agree that it might generally be useful to have a standardized
date value that allows for easy comparison of values, I think on the
other hand that the overwhelming majority of projects will stay within
one calendar scheme and will be able to perform all relevant
calculations with normalized versions of dates within their specific
At least for our project regarding medieval sources I can be confident
that all our dates will be Julian dates and that we will not have to do
any calculations or comparisons taking into account any other calendar
Thus it would be a major advantage for us to be able to state in the
header of our documents (or even in a certain attribute of the date tag)
what calender we are actually using. As the @value attribute is reserved
for (proleptic) Gregorian dates, we would need another attribute that
allows us to enter normalized date values.
But I think it's not only a matter of convenience. There are also some
good reasons to use normalized Julian dates in our project and I am
pretty sure that the same arguments will be valid for projects using
other non-Gregorian calendars.
1. Modern scholars of medieval and ancient history are not used to using
the proleptic Gregorian calendar and I guess they never will be. So we
lose a good deal of readability of our documents if we do not provide
for a way to include normalized Julian dates.
2. If you have only a Julian year, it is not possible to use a simple
value for the corresponding Gregorian year. You will almost always have
to use a time span with months and days.
3. Often we encounter incomplete dates and it is much clearer to have
the same pattern for dates, such as 1111-12-00 instead of 1111-12. (This
refers to the usage of zeros within date patterns as described by Karl
Märker in Feature Request 1547904.)
4. If you have an event happening Christmas 1111 you do not expect
1112-01-01 (the proleptic value): Reading this value you will not be
able to draw a connection to Christmas, in fact not even a connection to
the year 1111, intuitively.
5. If you only know something happened on Christmas, for years before
1582 gMonthDay "--12-25" is wrong (and due to the varying differences
between the Julian and the Gregorian calendar I can see no correct way
of expressing this kind of date in a suitable manner). In fact, we quite
often encounter dates like this, as many days in the liturgical year are
tied to certain dates in the calendar (think about the feast days of
saints) and often events are said to have happened within the n-th year
of the reign of a certain king or emperor.
To summarize, I very strongly support Karl Märker's feature request.
From my point of view it would be the best solution to stick with the
requirement to use Gregorian values within the value attribute, but to
allow another attribute containing a normalized version of a date in any
given calendar. While I am only familiar with Gregorian and Julian
dates, I guess that it might be possible to use the pattern, mentioned
by Karl Märker in the feature request or even something simpler like
and be able to give a numerical, normalized value of dates in most of
the common calendars.
I'd be interested in any thoughts about this or any hints as to how it
might be possible for us to use normalized Julian dates in our project.
Monumenta Germaniae Historica
Projekt Digitale Monumenta (dMGH)
Postfach 34 02 23
D - 80099 München
+49 89 28638-2380