NAME

       DateTime::Calendar::Julian - Dates in the Julian calendar

SYNOPSIS

         use DateTime::Calendar::Julian;

         $dt = DateTime::Calendar::Julian->new( year  => 964,
                                                month => 10,
                                                day   => 16,
                                              );

         # convert Julian->Gregorian...

         $dtgreg = DateTime->from_object( object => $dt );
         print $dtgreg->datetime;  # prints '0964-10-21T00:00:00'

         # ... and back again

         $dtjul = DateTime::Calendar::Julian->from_object( object => $dtgreg );
         print $dtjul->datetime;  # prints '0964-10-16J00:00:00'

DESCRIPTION

       DateTime::Calendar::Julian implements the Julian Calendar.  This module implements all
       methods of DateTime; see the DateTime(3) manpage for all methods.

METHODS

       This module implements one additional method besides the ones from DateTime, and changes
       the output of one other method.

       •   gregorian_deviation

           Returns the difference in days between the Gregorian and the Julian calendar.

       •   datetime

           This method is now equivalent to:

             $dt->ymd('-') . 'J' . $dt->hms(:)

BACKGROUND

       The Julian calendar was introduced by Julius Caesar in 46BC.  It featured a twelve-month
       year of 365 days, with a leap year in February every fourth year.  This calendar was
       adopted by the Christian church in 325AD.  Around 532AD, Dionysius Exiguus moved the
       starting point of the Julian calendar to the calculated moment of birth of Jesus Christ.
       Apart from differing opinions about the start of the year (often January 1st, but also
       Christmas, Easter, March 25th and other dates), this calendar remained unchanged until the
       calendar reform of pope Gregory XIII in 1582.  Some backward countries, however, used the
       Julian calendar until the 18th century or later.

       This module uses the proleptic Julian calendar for years before 532AD, or even 46BC.  This
       means that dates are calculated as if this calendar had existed unchanged from the
       beginning of time.  The assumption is made that January 1st is the first day of the year.

       Note that BC years are given as negative numbers, with 0 denoting the year 1BC (there was
       no year 0AD!), -1 the year 2BC, etc.

SUPPORT

       Support for this module is provided via the datetime@perl.org email list. See
       http://lists.perl.org/ for more details.

AUTHOR

       Eugene van der Pijll <pijll@gmx.net>

COPYRIGHT

       Copyright (c) 2003 Eugene van der Pijll.  All rights reserved.  This program is free
       software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

       DateTime

       datetime@perl.org mailing list

       http://datetime.perl.org/