Extend the General Roman Calendar with National or Diocesan data

The General Roman Calendar can be extended so as to create a National or Diocesan calendar. Diocesan calendars depend on National calendars, so the National calendar must first be created. The first step in creating a national or diocesan calendar, is to translate the data for the General Roman Calendar into the language for that nation or diocese. (see Translations) A National calendar may have some festivities in common with other National calendars, for example the patron of a wider region. In this case, the festivities for the Wider region should be defined separately, and if applicable should be made translatable, then the Wider region should be applied to the National Calendar.