This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
 Miscellaneous`Calendar` This package provides a unified treatment of the basic calendar operations. The main idea is to treat the calendar as a generalized number system, so that days, weeks, months, and years are thought of as generalizing the digits of a number in a given base. A detailed analysis of how this is done is given in the third chapter of Computational Recreations in Mathematica, by Ilan Vardi (Addison-Wesley, 1991). The key to the implementation is Mathematica's ability to work consistently with general objects. Calendar computations using the standard calendar. This loads the package. In[1]:= < Julian] Out[5]= The Gregorian calendar is 13 days ahead of the Julian calendar. In[6]:= CalendarChange[{1992, 2, 29}, Gregorian, Julian] Out[6]= Here is a conversion into the Islamic system. In[7]:= CalendarChange[{1992, 2, 29}, Gregorian, Islamic] Out[7]= This gives the first day in the Islamic system, the date of the Hejira. The date is given in the Julian calendar because the Gregorian calendar was not used before 1582. In[8]:= CalendarChange[{1,1,1}, Islamic, Julian] Out[8]= Dates of holidays. In 1945, Easter Sunday was on April 1. In[9]:= EasterSunday[1945] Out[9]= This uses the pre-Gregorian computation, but the result is given as a Gregorian date. In[10]:= EasterSundayGreekOrthodox[1984] Out[10]= This gives the date of the Jewish New Year in the Gregorian year 1997. In[11]:= JewishNewYear[1997] Out[11]=