You say "No software project cares"... but I'm sure there are pieces of software out there used for dealing with historical/archeological data and have to deal

You say "No software project cares"... but I'm sure there are pieces of software out there used for dealing with historical/archeological data and have to deal with stuff like this :) I would not want to have to work on it. Archeologists must spend a lot of time reconciling different calendars and all the changes that have happened over the years. And yeah, if I go the rest of my career never having to work with calendars or scheduling I'll be a happy man.